Ranked mmr issues

Just played a game where the lobby was filled with d2's/d3's, but on my team was also queued a, 1000 game p1 player.

I don't understand how a player with that skill level is being put into a diamond ranked match? Is matchmaking bugged or what? It is extremely unfun to have to play support to an adc who is completely outclassed and out of their depth?

To be that guy, wtf rito????