I understand that you can report them but this is not immediate and you could be stuck in a game with them for an 45 minutes or even an hour with nothing you or your fellow teammates can do to stop it where you with all your wisdom know that with the current game state it is not possible to win (1 flex slot to the enemies 4, with 12,000 souls in your pocket unable to be used). In some situations you may be stuck in a game with bad players who have no idea/a poor idea of how to play or how to win, as a result the enemy who has good players gets a lead and your team filled with bad players who couldn't even play well when even, are forced to play from behind. Do you want to be stuck in a game like those especially if you don't get the character you enjoy the most? Just some food for thought.