When people complain to Cloudflare about neo-nazi material, Cloudflare sends their personal information to the publishers of that material, who sometimes use it to harass and threaten those that complained.

I wonder, does Cloudflare follow this same nasty practice for all the sites that use it?

I agree with Cloudflare, however, in opposing attempts to ban neo-nazi sites. Freedom of speech includes the freedom to take a position we disagree with, even one we despise. Remember, there are people who despise your views, too, but they should not be able to kick you off the internet.