Freedom of speech and deplatforming are completely compatible. It is the duty of every citizen with a voice to make it heard that fascists are not welcome anywhere, and that anyone who wants to continue interacting with the rest of society must refrain from associating with the cretins.
The best way I have heard it phrased is that tolerance is a social contact. By being intolerant, they break that contract, and we have no obligation to follow through on our part if they don't do their part.
Terminally online leftists and being mad at liberals for positions they don't actually have, name a more iconic duo!
We have enough to disagree with them over without just making shit up because a trophy hunting concern troll managed to convince you they're a dyed in the wool end of history theorist