You mean thank you riot for making a game that I like to play? You expect riot to be able to stop these trolls? Thank the playerbase, not riot. Misdirected hostility at its best. There's always gonna be trolls in any game. People see how upset it makes people on league, so they love doing it here, because of threads like this.
Not saying you're in the wrong for hating it, but maybe don't voice your frustration online because that only attracts more trolls. Riot could crack down and hand out more and more permabans than they already do, but more trolls will come. Millions of people. That's a huge number. How could they filter out all the trolls, when there's MILLIONS of potential trolls.
Your frustration should be directed towards the trolls, not the street they hang out on. Riot made a great game, and they obviously want to keep their profits up and make it enjoyable to attract more people for more profit. They aren't just sitting on their asses, thinking it's best to just do nothing about trolls. They want to get rid of em cuz it makes people leave their game and not want to play. But combating trolls is probably much harder than you think, considering you said thanks for nothing. You must think it's easy or something.