One of the main objections to Calvinism is that it casts God as a cruel monster who creates people in order to arbitrarily condemn many of them to hell. While I think that understanding is a distortion of Calvinist theology, it nevertheless contains a grain of truth and poses a seeming problem to the omnibenevolence of God.
But is Calvinism necessarily incompatible with an infinitely good God? Not if universalism is true! And of the five points of Calvinism, none is in direct conflict with universalism. The only potential problem would be with the doctrine of limited atonement, but given universalism the point becomes moot, since Christ’s atonement would be “limited” to all people.
This is not to say that Calvinism is true or that universalism is true or that Calvin was a universalist (definitely not true!) or that we should adopt a theology merely to avoid a problem. But I find much to be commended in Reformed theology: it makes a great deal of sense biblically, theologically and philosophically. And I think we should all be, at the very least, hopeful universalists.
As someone who has at least a provisional flag in both camps, the intersection of Calvinsim and universalism is intriguing. The possibility that God is completely sovereign over creation and that we will all ultimately be reconciled to him has emotional and theological appeal. You won’t find many Calvinist Universalists (perhaps Barth was one), perhaps because both positions have been marginalized by an opposition that fails to truly understand them, but they are deserving of wider consideration, especially in relation to each other.