Raging giving up kats roaming?

First I played normal someone picked kat and went mid they died once said OMG FUCK YOU to the guy that killed her and came back like anyother person will do and die again and says I give up fuck this then afk for like 1m comeback and feed the enemy team saying dumb shit we ff

Next game I went to go play flex to get out of placements in my 7/10 someone picked kat talking like they are a good team get in game and just fucking feed the enemy team and talk dumbshit while raging and now I'm gonna be a bronze because of riot making it wins is ur rank and not how u fucking play :')