@Riot, why do we have to suffer loss of LP if a teammate trolls/intentionally feeds in ranked?

Riot,

It's messed up how the serious players in ranked who are dedicated to winning are constantly screwed over by the ragers/trolls/kids/intentional feeders that cost us the game and the LP. Just today, I decided to play a ranked match because I hadn't all summer (I avoided it because of the kids out of school for the summer), and my game started out okay. We invaded and we got first blood, I died to a Cait trap and Teemo poison, and Fizz exploited my bad start, but down on bottom lane, Nidalee sup was lagging and constantly dying, therefore pissing off my adc Ashe. As my jungler Cho'Gath and top Garen got fed, and I got better as the game went along, Ashe constantly started to bitch about how we wouldn't win, even though Garen and Cho were carrying. She still wasn't optimistic that we would win, went to the store, and SOLD ALL her stuff. She then passed me in lane and fed Fizz another kill. Therefore it was now 4 v 5 again after Nidalee came back, and the game was lost as Ashe would not help. We lost a game we could've won because of this feeder.

So I ask you Riot, why do we have to suffer due to them? I lost 21 pts because of it. It's not fair even if we report them. 5/10 times they will be punished, slapped a chat restriction or ban if lucky. But the people who tried to win still lost LP because of them.

Please. Make a system to where we don't have to suffer-give us a loss prevented or don't make us lose LP. Give us like a +0 or something.

Sincerely,

a fustrated and tired player