I think it depends on which ones you're using. There are some facebook groups and subreddits I use that still feel very much like a small-forum, where people are generally good and helpful and many of the users are regulars. I haven't seen any discord rooms like that except for some ones that are direct spinoffs of the facebook groups and subreddits I mentioned, so that seems more like a credit to the users than the medium.

I think they have to be pretty niche, though. But to be fair, forums of the old internet also had similar issues where once they reached a certain size the experience was different/worse than when they were smaller.

"As an idea or subject gains wider popularity and interest, the level of passion and laser focus on the _outcomes_ of the idea or subject gets diluted to the average level of understanding of the interested audience for the core subject"

(my weak attempt at describing this issue)