I'm not aware of a single issue which has been effectively banned from public discourse due to being moderated on social media, nor any person who has been unable to continue public life or communication, for the same reason. Even "vaccine critical" discourse during COVID was rampant during the time when, supposedly, social media platforms erased it completely.

The "sway" that social media platforms have over public discourse is often vastly overstated for political ends, certainly compared to that of governments.

And the real problem is, if you consider the ability of social media platforms to moderate content to be harmful, the only solution is to have government limit the free speech of those platforms and those who participate on them by coercing them into publishing speech they don't want to, which cedes power to a potentially even worse entity. People are so terrified of the power social media has now - as an extension of the general social panic against "the left" - that they're willing to throw the baby out with the bathwater. Facebook can ban me from their platform but at least they can't send goons to my house and ban me from life.