I see a lot of shitposts and edgy humor, which is fine; so I initially thought the instance was more of a shitposting community rather than a serious one advocating communism. Or is it?

This is a general purpose forum for communists, anarchists, and fellow travelers. Site culture encourages both serious political discussion and shit posting. We are very earnest about our politics. Having been locked in this website with only each other for three years, we have developed lingo, in-jokes, and a posting style that can be easily misunderstood by outsiders.

It's the only thing I've ever seen on the internet that feels like actually hanging out with friends. There are many users I recognize, but even the ones I don't, I still get that vibing-with-like-minded-folks vibe.