Even if you think the current usage of deplatforming has been positive, it poses a huge black swan risk. If our major communication platforms expose a centralized censorship mechanism, that becomes a deliciously tempting target to be leveraged by authoritarian regimes.

Even if I trust the Twitter mod team, what's to stop tomorrow's jack-booted thugs from shooting the Twitter team and seizing control of the servers? I'd much rather we as a society move to decentralized censorship-resistant networks while we still have the freedom to openly build and advocate for them.

I really doubt that banning Hitler's social media accounts in the 1920s would have done anything to stop the Nazi rise to power. Whereas in the 1930s, rest assured that centralized platforms would have made the Gestapo's life a hundred times easier.