I'd rather have a toxic player that is decent than a positive one who is total garbage.
Toxic players bring their team down and are more likely to make everyone perform worse. A positive player who makes the environment positive can rally their teammates and improve everyone's gameplay. Ever thrown a game, or fountain afk because you think a game is unwinnable? Pretty sure toxic players do that.
Seriously.
I'd rather be a garbage player than a garbage human being. Here's a little scenario from based Sky:
Toxic Player: "But I need blue to win lane!"
Jungler: "Well you need to be a decent fucking human being to win life!"
Blue buff is not worth being an asshole over, and neither is this game.