Constitutional protections on free speech are not intended to be sufficient for a society where issues are decided by debate. They're necessary--since otherwise, sooner or later, the people in power are going to decide that your criticism of them is very very wrong and must be made illegal. But not sufficient.

To have a society with robust discourse, it is necessary to be able to be wrong. Badly wrong, even. It's not necessary to allow calls to violence. But it is necessary to allow even rather horrible ideas to be floated for the ideas to be shot down rather than the people.

For instance, you've floated the idea that saying dumb offensive stuff in a fraternity is cause for doxxing and expulsion.

Now, I think that's an awfully severe extrajudicial punishment to advocate for. I think that this would necessarily lead to a crippling fear of dissent, destroying any possibility of meaningful democracy, and leading to autocracy. Do I think you should be hounded and doxxed for these really bad ideas that threaten the safety of everyone in the country? No. I think someone should explain patiently why this is a bad idea, and if the arguments do not seem persuasive, one could then try to appeal to additional arguments and evidence.

Fear-based conformity is a recipe for decisions being made solely on the basis of power and reputation, not on what is actually the case, or what actually will happen. Imagine, for instance, if anyone questioning whether trans fats were healthy had been expelled, doxxed, and rendered unable to find work!

It's reasonable for society to express scorn over bad ideas, and to some extent one's reputation for spreading bad ideas ought to make one a little wary. And of course if violent, harmful, destructive actions are goaded by speech, we can certainly limit that. But you draw the line at the same place that authoritarians do, and that's not a safe place for it to be. Mob justice is no wiser and no gentler than governmental justice, if allowed to proceed unchecked.