The problem with platforms advertising that they’re free speech platforms is that you’ll get a lot of people who gives no flying fucks about freedom of speech, they care about that specific discourse that got them banned from other platforms, and only a few people who actually care about free speech as a principle.

And that backtracks all the way into

1. The false dichotomy that freedom of speech is binary (either you have it or you don’t). It’s quantitative - you have more or less of it, never full or empty.
2. That nasty, robotic tendency of plenty social media users to stick to the words themselves, instead of the underlying concepts. Cue to “ackshyually”. In this case “free speech” makes them think about some random law of some random country, what it allows and what it doesn’t, instead of thinking on the principle itself.
3. The incorrect belief that only people above you in a hierarchy can lower your freedom of speech, when we do it all the time. (For example: specially stupid users reduce the freedom of speech of the others, as they discourage their participation.)

Once you work around those three, you realise that, in a lot of situations, forbidding a discourse actually increases the freedom of speech of some other group; so sometimes you need to do it to maximise the overall freedom of speech of all parties involved.