Not a value judgement or call-out or anything, just some observations about /a/. It's not even my wheelhouse, I just lurk there sometimes. And yes, I know
>>8873 is a copypasta.
/a/ has a lot of colloquial rules that you have to lurk there in order to know. Some kinds of material that would be considered NWS elsewhere on the site is permitted on /a/. There is a very strict enforcement of "no request threads" which quite literally gatekeeps users; but asking for recommendations during the course of discussion is permitted, so users have to engage with the discussion in order to at least get introduced as a newbie. There is a "no generals" rule that is enforced quite well, despite the several threads that are functionally generals despite not being marked as such -- looking at you, buyfag and isekai generals -- so this creates a low-effort filter as well: users have to at least be able to "play ball" with the moderation and the others users in order to be able to post certain things. Anime is a visual medium, so the imageboard format suits the discussion style well: imagine trying to talk about anime on some other site where you have to find a host for your image, and then you need to link or embed it... yuck! Discussion is rarely approachable unless you're familiar with the content: there's so much anime and so few things to go off of, that unless you know what you're looking for, you won't find it. If you open a random thread on /a/ and don't know the show that's being discussed, it can be absolutely impenetrable.
tl;dr gatekeeping.