The thing about online multiplayer games is that it's impossible to eradicate all negative players. Even if Rito does give out perma bans, they will always exist.
- There are ways to trolling while bypassing the summoner code.
- And since all games aren't recorded, there's no real way to tell who's doing what solely based on the chat log.
- And most importantly, the enemy team won't report the troll on your team if it caused them to win, or if they just don't care since it's not their problem. Without more than one vote, it might not even be seen as a case. (Not entirely sure, correct me if I'm wrong)
The only thing to do is mute and report, and that's only effective if the other members of your team goes along with it.
For me personally, I just ignore and play. Unsportsmanlike players aren't worth chatting to. And trolls are going to do whatever they want anyways, so just hope that the community is willing to put the small effort of pressing that red button.
Just gotta deal with the faults.