Unfortunately, this doesn't stop the toxicity. I always found it strange when people insult me for being bad. Like, dude, we have the same MMR. You are as terrible as me!
I often wonder if those people actually are more skilled than their MMR implies, but they lose a nontrivial amount of games by being toxic and tilting teammates. Cursed to always be surrounded by inferior players because of their own attitude.
Perhaps, some people could have a higher MMR with a better attitude. But it's more likely that the vast majority of them simply don't see how bad they are or they can't accept it.
Skill-based matchmaking sounds good on paper —and maybe it does help to an extent— but it doesn't work all that well when you take into account the top performing players will routinely play under low level, alt smurf accounts, to grind and keep the high rating of their main account intact.
Yep. I know there was recently a very dumb push against SBMM, but it's required for modern gaming in most contexts now. There's a lot more players now, so some of them are incredibly skilled, and others are incredibly bad. We don't really want them mixing if they're playing competitively.
It also used to be that most of our games were pretty casual. Most of CS wasn't the competitive DE mode we all play today. There were tons of servers playing custom silly game modes (and there still are!), but most players only play comp or (confusingly) still competitive unranked modes. Most games don't have casual game modes anymore that are designed for just goofing around.