Riot Condones Trolling

My buddy played a ranked game and his jg picked Braum and was obviously trolling during the game. He didnt clear the first camp for about 5 min got a max of 30 cs by 20 and ended the game 1/6/0. The one kill he got from using his q to kill an ignited target that would have died to his teammate, he then danced at them after taking the kill from them. The team obviously lost the game due to the Braum trolling the whole time but that's not the worst part. The Braum then received an S ranking at the end of the game letting him know he did a good job in his role, except he didn't. He can now freely believe that's what he is supposed to do and that the game wasn't his fault, because that's what Riot has told him.