Is it banable?

I just played a ranked Dynamic Queue game (solo), and someone just decided to troll because his pre-selected champion got banned by a teammate who wasn't looking (he still apologized for it), they jumped on a fight and then I jumped into the fight to try and calm this guy down (wich was impossible), then he decided to take over MY role wich was Jungle (he got Top) and force me and the other guy to either play with him trolling in the jungle or leave the game, this guy had to play Poppy Top when he was asigned Bot and I had to go Kha'Zix Bot (reported him ofc)... I've been getting this type of champ selects since the system got released and I got placed into Platinum, for some reason Platinum players have such a bad behavior. So, is it banable? The guy who banned the pre-selected champion can also be punished? Answer please
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