Thing is, that if we take UnderstandingIsContagious seriously, and understand ACultureOfConspiracy then we know ideas spread through geographical / topological proximity. So of course "deplatforming" is an obvious "sensible" measure to firebreak and stop the spread of ideas we don't like.
And of course, the fight about FreedomOfSpeech is never "innocent" in the sense that people who want to spread the "bad ideas" are going to want to complain on grounds of free speech. Not on the grounds of defending the ideas themselves.
The thing is you can't have a sensible discussion about deplatforming rights and wrongs without :
a) acknowledging all the things we now know about how ideas spread in networks. We've learned a huge amount about this in the last 20 or 30 years as we've seen and studied the growth of the internet. And we can be pretty sure that when people have access to new ideas they will (statistically) adopt them. You can't still, in 2022 believe that "if we maximize people's exposure to fascist ideas, this helps us all understand and refute them better". No, we must assume that if we invite fascist ideas onto our platform, and expose more people to these ideas, at least some proportion of new people will therefore adopt them.
To believe otherwise is a wishful thinking that doesn't accord with everything we know about how ideas spread.
b) acknowledging that there is no "neutral" way to detach the value of freedom of speech from the questions of the value of the speech itself. If you support freedom of speech for ideas you don't like and don't agree with, you ARE supporting the dissemination of those ideas, the adoption of those ideas, and the consequences of them. (FormAndContentInFreedomOfSpeech)
Yes, of course, you would like for that not to be the case. You would like for your support to be somehow bracketed off, only about a higher-level principle of freedom and not at all connected to the content of the ideas themselves.
But that can't really be the case.
It's again a kind of wishful thinking. That the world isn't as messy as it is. And that human brains don't work the way they do.