Playing with the intention to lose?!

I really don't make posts like this very often, but I can't wrap my head around people who play this game with the intention of losing. I was just in a game where ADC and Support were left to pick. I chose ADC but offered the other player the role if they preferred it, stating I could support. She ended up going karma support, and within seconds of getting to lane died. As soon as she spawn she ran back to lane, warded, poked once, then tried to initiate a fight while she was level 1, I was 2, and they were both 2. She died. I backed up and kept farming.

After this, our mid laner died a bunch, our top laner also, and our jungler went 0/7, though, the entire time, instead of trying, they were just all chatting saying things like "omg ur cheating on me I thought you loved me Riven" then running under Rivens tower and dying.

What is the point in this?! I don't understand?!

The worst part was, Karma was gold 3... how is holy hell did she make it to gold 3 with this mind set? On top of that, our mid laner was bronze 4. Why am I being placed with bronze 4 level players?! I know I'll get comments like "you get placed with your own skill level" but you really don't.

I've encountered games like this far too many times. I get it, some games you lose, but I don't want to lose the game because my entire team doesn't want to play seriously. So frustrating.