If you look at 4chan vs Facebook/Twitter, you'll see different behaviours.
4chan is extremly politically incorrect but it's also the only place where you can find what people actually think, without filters. Facebook and Twitter are a collection of echo-chambers of people saying all similar things because they're afraid of being judged by their side or society at large.
I still try to be nice when I'm anonymous but, more importantly, I'm comfortable sharing what I think only when I'm anonymous.
I don't want to link my political views to my name, I don't want my well paying employer to know I'm not as woke as them.