There are plenty of multiplayer games I adore. However, it seems like every community has these "brain dead", patronizing, or out right toxic elements that are just nasty. I'd rather debate politics than make suggestions in some gaming communities because the responses are just so ... annoying.
As an example, I once dared to suggest that a game developer implement a mode to prevent crouched status from rendering on death cams so that players that are bothered by t-bagging could avoid it (after a match where a friend rage quit because someone just kept head shotting him -- possibly with cheats -- and then t-bagging). This post got tons of hate, and like -50 upvotes on reddit because of course someone should be forced to watch someone t-bag them.
Another example on a official game forum... I made a forum post suggesting Bungie use Mastodon (or really just something else being my intent)... The response I got was some positivity but mostly just "lol nobody uses that sweetie" and other patronizing comments.
Meanwhile studios themselves often seem to be filled with developers that understand this stuff is a problem, and the lack of sportsmanship (or generally civilized attitudes) does push away players. It just doesn't make sense to me that no studio is saying "get lost" to these elements or implementing anti-toxicity features. I just want to play games with nice normal people, is that really so much to ask?
Which is extremely unfortunate. WoW forum threads could be a cesspool in a matter of seconds.
Anyway, as others pointed out, the main problem is competition. The more competitive a game is, the more invested some people get. The more invested you get, the more likely you are to rage at losses and behave like a monkey against a losing opponent. Hell, you don't even need to be a player to feel invested, just look at people that worship their sports team.
For online games, companies just shrug and point to their automations for trying to control toxicity (Riot Games probably being the "best" in the area), because it's much easier to automate than to come up with a solution.
My main recommendation is to avoid super competitive games. If you want to play those, then you're probably better off trying to find small groups of colleagues for that. In ye olde days of games coming with the server-side executable, these groups were called clans. Quake, Unreal and Jedi Outcast had lots of them.