I think there are two basic motivations for Universalism. One is a genuinely charitable hope that none will choose eternal separation from God that really is rooted in a desire for the good of the other. People like St. Gregory of Nyssa held this view out of his deep respect for and believe in the all-conquering love of God and he is vastly better man than I will ever be. And since he is a saint, it is clear his view is within the pale of permitted Catholic opinion and not in the least heretical (just as long as you don’t try to bind everybody else with different views.) I can respect it even if I find it difficult to square with the data of Scripture and Tradition. It’s not like it will affect the outcome since the people who hold this theory are not the Judge and whatever will be will be. I hope they turn out to be right and if they are and I am wrong, then booyah! I’ll be delighted to be wrong.
The other reason for Universalism is, I think, sinister and does affect the outcome, at least for the person who believes it. This is Asshole Universalism and proceeds from the privileged demand of selfish assholes to never have to face any consequences–ever–for being selfish assholes. Nazis like my fellow Catholic Nick Fuentes hold such opinions and it appears the sole fruit of such opinions in their case is not a growth in faith, hope, or love, but simply a tendency to become more and more of a selfish, hurtful, hateful asshole who thinks he can degrade into total depravity and get a gold star from God. He may be in for one Hell of a shock, literally. God grant him repentance through Christ our Lord.
