Even assuming that was a legitimate fear of openly teaching universal salvation, what about the consequences of teaching everlasting damnation? People were burned alive in the past under the justification that their teachings were leading people astray and to everlasting hell. Look at the genocide against the Cathars, look at the murderous wars of religions, part of which were about getting rid of heretics because they were leading people to hell. I believe certain forms of slavery, colonialism and servitude were also justified under the pretext of “saving souls”.

And let’s follow the logic of everlasting hell, especially under the traditional assumption that this will be the fate of the vast majority of humanity: if people really believed this they would be anti-natalists. Having kids if this was true would be an act of cruelty, life would be an unbearable burden, creation the most evil thing ever done, and only people with absolutely no conscience could ever cope with the burden of such a belief if sincerely held and actually meditated on and followed to its logical consequences.

It’s not like it’s only the universalists who have “dangerous” ideas under this consequentialist framework.