I'm an atheist, but I've seen "atheists" intone their beliefs, even though there was no one around to convince, like it was a profession of dogma from a Mass. There are definitely some "atheists" around who approach it from more of a tribal affiliation perspective, not an intellectual one.

Even the most intellectually sound movement can become toxic.

https://www.lesswrong.com/posts/ZQG9cwKbct2LtmL3p/evaporativ...