I will first concisely explain the traditional Arminian and Calvinist views, directly addressing (in bold type) the OP's question in the section on Calvinism. I will then introduce one helpful and popular way of comparing the distinctions between traditional Arminian, Calvinist, and Universalist views. At last, I will provide two example alternate views, though there many more.

Calvinism and Arminianism function as internally-consistent rational systems for explaining how God can allow some certain people to become condemned ultimately.

Arminianism

Arminianism remains consistent because it claims that God loves everyone unconditionally, but is unable to save everyone he loves because his character prevents him from infringing upon human will (which assumes that it is not possible to save everyone without infringing upon human will).

Calvinism

Calvinism remains consistent because it claims that God is in fact able to save everyone (regardless of human will), but he has chosen to hate some people in order to demonstrate his glory through wrath and to save other people in order to demonstrate his glory through grace. Thus, he chooses to not save everyone from condemnation. God is not omnibenevolent in the unlimited way in which the OP is using it; God is benevolent to all creatures for some of the time, and some creatures all of the time, but not all creatures all of the time. His wrath as well as his mercy exists to demonstrate his glory.

These are the two most-popular integral Protestant non-Universalist solutions to the dilemma.

Thomas Talbott's Propositions

Thomas Talbott states the above synopses of Arminianism and Calvinism in other words, via his now-famous propositions:

(1) It is God's redemptive purpose for the world (and therefore his will) to reconcile all sinners to himself;

(2) It is within God's power to achieve his redemptive purpose for the world;

(3) Some sinners will never be reconciled to God, and God will therefore either consign them to a place of eternal punishment, from which there will be no hope of escape, or put them out of existence altogether.

If this is indeed an inconsistent set of propositions, as I believe it is, then at least one of the propositions is false. Calvinists reject proposition (1); Arminians reject proposition (2); and universalists reject proposition (3).

(See "The Inescapable Love of God" by Thomas Talbott for more.)

Two Examples of Views Which Are Neither Arminian, Calvinist, nor Universalist

C.S. Lewis' View

It is interesting at this point to note here that C.S. Lewis, in "The Great Divorce", takes something similar in kind to the Arminian view, but changes it sufficiently to make up a rather distinct view. He attempts to show how God never gives up on redeeming souls, so long as there is hope. God provides the means of salvation for perhaps millennia after our deaths, and does not operate his will to condemn anyone ultimately, but, despite his grace, many people will reach a point, by the operation of their own wills, from which God in his foreknowledge knows they will not return. Once that point is reached, in God's wisdom, he will, as it were, "close the gates of Heaven", in order that his grace will not be mocked without end. This results in a view that has aspects of all three primary systems: repentance after death (from Universalism), humans willing themselves into ultimate condemnation (from Arminianism), and God ultimately refusing his grace to certain people (from Calvinism). I find this to be an elegant way to resolve the Biblical and theological difficulties.

Molinism

Molinism is another attempt to reconcile the difficulties between Scriptural texts which seem apparently Arminian and texts which seem apparently Calvinist. (This view is quite popular among, for example, Baptists.) It centers around the concept of "Middle Knowledge". "Middle Knowledge" is the theoretical knowledge of not only all that has happened, all that is happening, and all that shall happen, but all that could happen and all that could have happened. Molinism asserts that "Middle Knowledge" is indeed possible, and that since it is possible, God of course has it and he takes this knowledge into account in his work of redeeming Creation. The result is that God, before the foundation of the world, peered into all possible timelines and saw the best timeline for maximum salvation (and/or maximum glory, depending upon whether one prefers the Arminian or the Calvinist view of God's goal); he then determined from before time who he would save and who he would condemn, making both a sovereign pronouncement of his grace and an affirmation of humans' use of the power of volition which he willed to grant them.

How does Calvinism explain how an omniscient, omnipotent, and omnibenevolent creator could NOT have a plan for universal salvation?

...

it seems illogical that a loving creator with perfect and complete knowledge could be considered incapable or unmotivated to ensure the eventual salvation of all His created earthly beings.

Understanding God's purposes is much easier if we do not impose non-scriptural ideas of perfection on Him. One such idea is that God cannot be 'torn' or have internal emotional conflict. Related is the idea is that God's perfection implies an inner simplicity and that should be reflected in a simple plan for the universe. In contrast, I suggest that scripture paints a picture of a complex and emotional God without ever deviating from a full acceptance of:

• His total control of all things from start to finish
• His transcendent knowledge and understanding
• His unrivaled and indeed shocking love and tenderness towards even His enemies
• His fairness, justice and determination to establish His rule fully in the fullness of time

Many passages speak of God's heart-felt desire for universal salvation: that every man may repent and return to God with his heart. New Testament verses expressing this desire include 1 Timothy 2:4 and 2 Peter 3:9 among many others, but the degree of emotion and heartbreak God experiences is perhaps most evident in Ezekiel:

• Have I any pleasure in the death of the wicked, declares the Lord God, and not rather that he should turn from his way and live? _{Ezekiel 18:23, ESV}

• Say to them, As I live, declares the Lord God, I have no pleasure in the death of the wicked, but that the wicked turn from his way and live; turn back, turn back from your evil ways, for why will you die, O house of Israel? _{Ezekiel 33:11, ESV}

When set against the many passages that suggest that not all people are saved, we are forced to ask ourselves how to accommodate this with the fact of God's great compassion. If it is also accepted that God possesses power without limit, our only conclusion can be that God wants something else more. Both Arminianism and Calvinism accept this fundamental proposition, the former believing that God's desire to allow man freedom of choice is the 'greater good' He desires, and the latter believing that it is God's desire to gloriously express and enact His justice on the unrepentant:

• The Lord has made everything for its purpose, even the wicked for the day of trouble. _{Proverbs 16:4, ESV}

• ²¹Has the potter no right over the clay, to make out of the same lump one vessel for honorable use and another for dishonorable use? ²²What if God, desiring to show his wrath and to make known his power, has endured with much patience vessels of wrath prepared for destruction, ²³in order to make known the riches of his glory for vessels of mercy, which he has prepared beforehand for glory— _{Romans 9, ESV}

On a human level, God faces the kind of choice a kind and forgiving man might face if given the power of life or death over a murderer who had killed his son or daughter. Whatever moral stance we might take, perhaps no-one would deny the likelihood of conflicting emotions in this situation. The extraordinary way God deals with His choice, combining compassion, substitutionary atonement, justice, wrath, mercy and grace is the reason I am glad it is God who has to wrestle with this dilemma and not me.

Put simply, God's "omniscience, omnipotence, and omnibenevolence" speak of the impossibility of any external influence impeding their expression, not of the impossibility that God's own nature might be conflicted nor that one characteristic might affect the expression of another.

or in the words of Shai Linne: "...He loves the world for sure, but He loves His glory more!"