Why do people carry toxic players on their team?

I feel like my reports do nothing. There's always one person on the enemy team who's beyond better than the MMR and they carry players who are extremely toxic.

I mean I know it's not good to be salty about this but, I'm not supposed to be happy about it either. I've been extremely patient and I treat every new game with a calm mind and I don't speak until the end of the game in lobby.

I just feel like I'm not being rewarded for putting in extra effort and certain players on enemy team can do literally nothing and be toxic and still win because 1 person carried them.