Regarding toxicity

I have just received a two week ban for "inflammatory behaviour". Granted, I said things which definitely deserved it, but this is not what I want to focus on. This Yasuo on our team, literally trolled the entire game by leaving his lane top at level three after two deaths, then proceeding to go mid and die, then bot and leech xp and die. It wasnt tilting, it wasnt being new, any human being could tell he was INTENTIONALLY FEEDING. I, being a human being with emotions, let me frustration get to me, wanting to enjoy a game for once where this shit didnt happen literally every game said things I should not have said. Two weeks. Bam. Gotcha, I was a dick.

  Meanwhile, this yasuo said literly nothing the entire game, literally ruined the entire game with his behaviour, and then the kicker, he openly admitted to trolling in the chat logs but said "riot will never know". Lo and behold, I get a ban for loosing my cool at a player who was clearly trolling but knew how to "fly under the radar". How is this nonsense even allowed, you have players who get a ban for being human and lashing out at toxic behaviour, and you have these trolls ruining game after game but because they have not said anything "in game", they most likely go free. 

Guess it turned into a mini-rant, and I guess your allowed to literally do almost ANYTHING you want as long as you don't type. I was an asshole to one person in retaliation, and he ruined the game for 9 other people the entire time. Where is the justice? I take my two-week ban with stride, but I am literally muting chat after this incidence and never typing a word. Why have chat at all when It appears to me that it is the easiest way to get a ban.