Per a comment up-thread, I wouldn't place too big a bet on pseudonyms remaining pseudonyms forever. Sure, absent a real effort to unmask you, you'll probably be fine. But sustained efforts to figure out pseudonymous identities often succeed.
It won't even need a sustained effort once ai gets somewhat decent at analysing writing patterns. I don't think it will really matter if it's even that accurate, really, like it doesn't really matter to the police how accurate facial scanners are people who are looking for troublemakers will go with it anyway.
