Why is the MMR system killer based?

Since the new MMR system i got in games with several rank 20 survivors, who I just destroy in 3 minutes. These games are neither fun for me or for them. So I hoped, when i play a couple of games my MMR wont bring these people into my games.

This kinda worked, but the problem is that every killer in the game has a different MMR. This means, that for every killer I have to play 3 to 4 games, where I get rank 20s who just get completely obliterated.

We have 20 killers in the game. I have to play around 60 matches, before I have balanced games on every killer. And 60 games of this, is too much imho: https://imgur.com/a/W0Ceson

This kinda destroys the fun for players who are new to this game and people who play for fun.

I would like to see some arguments how this is a reasonable way to balance the game.