This might strongly depend on the corner of usenet you were in, but there were large and important groups where elitism was absolutely cancerous, and a culture I don't miss. I frequented German end English groups, and can say that it was much worse in the German ones. Absolutely condescending attitude towards newcomers if they "misbehaved" even in the slightest; you'd have the "n00bs" post and then a dozen replies by the regulars circle-jerking by dissecting the OP down to every little detail they did wrong and trying to one-up each other in sarcasm. A typical flex was the length of your killfile.
Web-Based bulletin-boards (phpBB, vBulletin, WBB, ...) quickly took over in the early 2000s, which had the advantage of having superior moderation tools (e.g. being able to remove spam after the fact), giving a more consistent experience to users. Bulletin boards still tended to have the elitist group of regulars compared to usenet, albeit less pronounced. Some/Much of this can probably also be attributed to the users of those boards being a new generation of Internet users, which just had a different approach and attitude, much like we see today with facebook vs. Instagram, YouTube vs. TikTok etc.
What managed to mostly kill Internet forums was probably reddit, which improved SNR a lot by having the up/downvote system, and while technically being even more centralized than bulletin boards, managed to grow so much by basically allowing their users to create subreddits, which would equal the sub-forums in bulletin boards, which only the board's administrator could create.