I don't understand people that wonder why trolls exist in this game
When said people, being your own teammates, deliberately challenge you to behave like a toxic person by banning your own pick intent. There are other instances as well, such as going afk while wandering around or farming in the jungle to avoid leaverbuster, inting, spamming pings etc. In those scenarios, you are helpless, there's nothing you can do to stop this. You can't say "Fuck it, this guy is an asshole. I don't want to keep playing with him. I'm outta here" and exit the game like you do with fps games for example. And that's what causes toxic behavior. Which, by the way, follows the player through the rest of his games and ruins his day or mood or whatever. Yet Riot only condemns said behavior and labels all the other things I mentioned as "having a bad game", even though they are doing it on purpose. These people are the ones that set the base for what clearly appears to be a toxic community.
Tl;dr: Most of the time Riot only cares about who is being toxic and nothing more and that does not solve anything.