The right to free speech is drawn from a US constitutional amendment, which says the US government can’t censor speech, but it has nothing to do with private platforms like this, much less individual responses to Nazi rhetoric. Nobody owes hate speech a free platform.
But these private platforms have a liability shield. If they have a liability shield, they shouldn’t be allowed to censor things.
they shouldn’t be allowed to censor things
I disagree, and so does US law. Abusive material shouldn’t be spread just because it can be.