They don't want you on there, they need your silence. Your posting about injustice gives them great fear. They don't want your unsolicited commentary on state of affairs. You are a friend only if you boost their propaganda. So yes, go hide away and say nothing and pretend the world is normal, you will eventually have to deal with it in the real world.
Matrix, session, simplex seems like a interesting idea too.
Not sure if signal allows anonymous-ish personas for their groups but simplex definitely does but out of all the options given, maybe irc is the most well known :)