That and you can instantly find a huge tribe. In the past you had to deal with others around you as well, which challenged ideas. Now you plug in to this huge tribe of anonymous people around the world and assume you’ve found the truth.
I think this is a misunderstanding. Social platform users have little reason to leave one platform for another. Censorship is one of those few reasons. Censorship 8s at a very simple level telling those with different thoughts to go start a tribe somewhere else.
Twitter isn't making good decisions. The killed Vine and gave Musicaly and then TikTok oxygen. Their censorship is giving rise to competitors.
Parler censors energetically also, it's just that it's owned by Breitbart rather than amoral profit-seeking VCs. The VCs censor whatever gets anyone upset, especially powerful people who can cause them legislative, legal, or tax trouble. Parler's owners censor sex and other things that don't agree with their ideological line, probably anti-racism, anti-military/police and positive depictions of the socialized functions of government (which can probably all be neatly grouped under "terrorism.")