The determinism of Calvinism is best understood as micro-determinism because it is not limited to the area of salvation (including reprobation). Well-known moderate Calvinist Millard Erickson, in contrasting Calvinism and Arminianism, says of Calvinism, “Calvinists believe that God’s plan is logically prior and that human decisions and actions are a consequence. With respect to the particular matter of the acceptance or rejection of salvation, God in his plan has chosen that some shall believe and thus receive the offer of eternal life. He foreknows what will happen because he has decided what is to happen. This is true with respect to all other human decisions and actions as well. God is not dependent on what humans decide. It is not the case, then, that God determines that, at times, what humans will do will happen, nor does he choose to eternal life those who he foresees will believe. Rather, God’s decision has rendered it certain that every individual will act in a particular way“ (italics added).
I must admit that when I was a Calvinist, it took me many years to come to grips with the rigorous comprehensiveness of determinism that is innate to Calvinism my first grade teacher said I was a very slow learner, and unfortunately she was disturbingly correct. Erickson’s words provide an example of why I maintain Calvinism actually requires that everything happens necessarily because neither the predetermined cause (antecedent) nor outcome can, nor could it ever, be altered by the choice of humans. There is a total rejection of the concept of contingencies, that which is the result of beings having otherwise choice.
Consequently, Calvinists should avoid obscuring such determinism by contending or even intimating that human decisions and actions are only certain to happen based upon God’s exhaustive foreknowledge (I am aware of why they like saying certain rather than necessary). The claim that many things are certain and not necessary is true of Extensivism since by God’s design, many outcomes could have actually been different had humans chosen differently, which they could have in fact done in the many scenarios that he sovereignly chose to be the case. 
Within Extensivism, there is a place for both contingent and unalterable scenarios. Some scenarios (contingent) result from human otherwise choice, allowing for different outcomes, while other scenarios are not the result of human libertarian choice, but rather, they are simply the result of God choosing to press a different eventuality. This may include sovereignly overriding man’s choice. God knows unalterable future events will take place because he knows what he predestined to happen (takes place necessarily), whereas he knows the result of the contingent scenarios because he is essentially omniscient; therefore, he cannot believe a wrong future proposition. To state it a little differently, a contingent eventuality is certain to happen because in creating man with otherwise choice, God comprehended in that plan to permit choice to actually alter some outcomes to originate a new sequence of events. This does not mean that he determined to make human choice relevant in all scenarios but only those that he so chose to be affected by human choice. To wit, some outcomes happen because he chose to disallow human otherwise choice to have an actual determinative influence upon the outcome.
For example, in Scripture God does at times override the will of a king in order to stop the king from using his freedom in a way that would disrupt the continuance of his plan of salvation (Deut 10:14; Ps 10:16; 22:28; 103:19). Therefore it can be said that Calvinism permits in actuality only divine determinism (things happen necessarily), whereas Extensivism permits both divine determinative causality (these happen necessarily) and divinely comprehended human contingencies (these happen with certainty, but not necessarily). That is to say, God has determined that some scenarios are temporally necessary while others are not and yet are still temporally certain.
The only thing that is necessary about man’s free choice is that if he would have chosen otherwise, God would have eternally known that choice because God knows everything and cannot be mistaken. That is to say, God can know a future event without causing the event so that it is certain because he is essentially omniscient and cannot be wrong, but such certainty does not make it temporally necessary. God eternally knows truth propositions about the future, and they are therefore necessarily true as they relate to God, but they are not temporarily necessary as they relate to man in time. Contrasted with Calvinism, actions and thoughts in Calvinism are necessary as they relate to man in time (they are the result of determinative antecedents), but actions and thoughts in Extensivism are only certain as they relate to man in time (they are the result of undetermined choices).
Granted, Calvinists usually reject labeling their decisions as happening necessarily and prefer the phrase being certain to happen; however, it seems to me, that actually serves the purpose of disguising the micro-determinism to which Calvinism is committed thereby enlivening the confusion of many people and this including both adherents and non-adherents of Calvinism regarding its omnipresent determinism. It is always important to keep in mind that compatibilism’s determinism (sometimes called soft determinism) is no less deterministic than absolute determinism (sometimes called hard determinism).
The only difference is that compatibilism seeks to make determinism and responsibility compatible; hence the name, compatibilism. However, it does so by defining free choice as doing what one ultimately desires rather than by diminishing the determinism of the position. This includes the reality that while the choice is considered free so long as one chooses what he ultimately desires, the origin of that ultimate desire is necessarily what it is because of determinative antecedents nature and past. Correspondingly, all of the choices that made up one’s past were themselves the result of determinative antecedents ad infinitum; hence, free decisions are in fact, given one’s past, not only certain, they are necessary or you do not have compatibilism.
A fundamental difference between Calvinism and Extensivism is due to an essential difference between compatibilism (to which Calvinism is committed) and libertarianism (to which Extensivism is committed). According to Compatibilism, the ultimate desire from which the free choice is made is the unalterable result of the past; consequently, if one knows the past of a compatibly free being, he can know the forthcoming choice with absolute exactness because it is determined by the greatest desire which was itself determined by the person’s past; therefore, given one’s past it happens necessarily as did his past. In contrast, one may know the past of a libertarian free being with absolute precision and still not know the choice the being will make because libertarian beings can make different choices given the same past.
Therefore, in the final analysis, all of the linguistically sophisticated and speculative philosophical endeavors of Calvinism to elevate God’s hatred of sin, desire for man to choose holiness, and salvific love for those who ultimately perish to a place of biblical fidelity are found to be crushingly wanting. The truth is that once this essential reality of Calvinism is disrobed of erudite, elaborate explanations, and removed from residing insufficiently scrutinized within the gauzily veiled temple of the “inscrutable mystery,” we find the unsettling and unbiblical truth that, according to Calvinism, every single person’s thinking, motives, choosing, and acting are precisely as God desired and designed for them to be. This is true regardless of their choosing or actions.
This includes every civilly kind thought or act extolled by God and appreciated by man, and every evil and horrifyingly malevolent act condemned by God and terrifying to man because they happened in every minute detail as God desired, intended, and predestinated them to be. Every person’s salvation and reprobation, as well as every person’s rescue from evil such as rape and murder, and every person’s abandonment to rape and murder are precisely as God desired. I do give credit and even admire the candor of some Calvinists regarding the truth of this Calvinist reality. Consider Gordon Clark’s comment in response to Arminians in which he asseverates, “I wish very frankly and pointedly to assert that if a man gets drunk and shoots his family, it was the will of God that he should do so . . . In Ephesians 1:11 Paul tells us that God works all things, not some things only, after the counsel of his own will.” Contrary to Clark, Ephesians does not say that God wills directly or indirectly causes everything, but rather that “he works all things after the counsel of His will” (Eph 1:11).
The reliance upon secondary or tertiary causes (or for that matter quaternary, quinary, senary, septenary, octonary, nonary, and denary causes), fails to assuage this determinative exactness one whit. According to compatibilism, everything is exactly the way God desired. As Clark exemplifies, some Calvinists do own up to this, and I do respect and appreciate them for doing so. However, my experience indicates that most do not. Most seem to fail to sufficiently understand and consistently own up to this essential of their system along with the entailments of such determinism (I assume they do this unwittingly rather than wittingly). Consequently, they obscure this reality of Calvinism by the employment of hollow distinctions, distinctions without an ultimate difference, which actually becloud the micro-determinism beyond recognition for the vast majority of detractors and adherents of Calvinism.
Such micro-determinism does indeed make the Bible’s ubiquitous commands given to both the saved and lost ultimately meaningless. That is the end of both fatalism and theological fatalism.
Yes, we do disagree on soteriology, but our preeminent disagreement really harkens back to who and what kind of God do we serve?
 Millard J. Erickson, Christian Theology, 3rd ed. (Grand Rapids, MI: Baker Academic, 2013), 326.
 In its general application, I use Extensivism as a synonym and better alternative to the term non-Calvinism.
 According to libertarian freedom, the latter does result in God being solely responsible for that particular decision rather than the individual.
 David L. Allen and Steve W. Lemke, eds., Whosoever Will: A Biblical-Theological Critique of Five-Point Calvinism (Nashville: B&H Academic, 2010), 292.