I can't speak to websites, but I can speak to community discords that have 10,000+ users where hate speech prevention is the reason that you have to provide proof of identity.
I have been on several such discord channels. In the ones I’ve been on, they got tired of people spamming nazi shit or the n-word over and over again, in addition to other forms of obnoxious spam. This isn’t so much an anti-hate speech protection as a general anti-abuse protection
(I spent a good few minutes trying to come up with a politer response than the following. I failed.)
Bullshit.
I keep seeing this “free speech” slippery-slope claim. It’s simply not true. I don’t know of a single mainstream or even semi-mainstream us or eu-based site that demands PII to stock “hate speech”. They ask for two main reasons:
1. Money. A confirmed “real” user is worth more.
2. Anti-abuse/spam. The sites are tired of dealing with bots.