the reason this game will die

I am sick of playing this game. Riot bans people who use foul language but won't ban people who are joining ranked games to piss other players off. to troll, to waste 50 minutes of my life. I used to enjoy this game so much in season three and now a days i join a game looking to have fun and win, instead i get people who intentionally feed because they didnt get their role in champ select. I get people who instead of helping out the team find it funny to throw the game. Then i get banned because I get frustrated and say three words to them and they all report me. Okay i dont care if you ban my account because there are other games out there that have ways to actively punish these trolls. But if you want to keep your player base then you should stop banning people who actually don't want this game to turn to shit instead ban these casual trolls going into ranked games just to mess it up for their team