Not necessarily because they were scared, but probably a lot of them got banned or saw their friends get banned from Reddit, and couldn't get back on because Reddit has quite strong detection for ban evaders, so after the initial anger period, Reddit just disappeared from their mind altogether.

You can openly be a white supremacist on Twitter now. The reason some people still aren't happy is because what they really want is to be able to have terrible opinions and not be disliked and shunned, which isn't possible. Social repercussions and censorship are different things.