One of the conclusions of a recent purge by Reddit was that it just pushed the banned users into even more radical spaces online[2].
Of course we all know about The Streisand effect, and one article suggests that censorship just draws more attention to the banned content[3]. If we assume that ideas are somehow "contagious" or "infectious"[4] then we're just exposing people to them even more.
> In any case, the only news on the topic that I’ve seen has been that election misinformation on Facebook/Twitter has dropped by 70% since the deplatforming happened on those platforms.
But the deplatforming didn't make those people go away, it pushed them to platforms like Gab and Parler, right-wing echo chambers. This is like an extreme version of a filter bubble. Remember, millions of people supported what happened at the capitol[5], and there is zero hope of de-radicalising people if the left and right aren't talking. If anything, both sides will get more extreme.
[0] https://en.wikipedia.org/wiki/Deplatforming#Twitter (see references)
[1]https://www.wired.co.uk/article/twitter-political-account-ba...
[2]http://comp.social.gatech.edu/papers/cscw18-chand-hate.pdf
[3] https://ro.uow.edu.au/cgi/viewcontent.cgi?referer=https://th...
[4]https://www.nature.com/articles/s41599-020-00546-3
[5]https://www.statista.com/chart/23886/capitol-riot-approval/