There was an episode of Madam Secretary that went into something like this and the comment that was the crux of the episode is that the issue is less social media than it is the hate, and, as of yet, we haven't found a way to make people stop hating.

Let's be real here, even if twitter etc banned all these people they would simply go back to 4chan or whereever to spew their lies or set up a million bot accounts, or create their own website to spread all this disinformation, or make a podcast or whatever.

THe problem isn't them, it's that people are willing to believe them, and, as of yet, we've found no way to make people stop being hateful idiots.