Why am I penalized for others leaving games?

Why is it that whenever I get into a series, bad things happen to me. For instance: the past two to three times I have been in a series there has been an AFK, an intentional feeder, or someone who builds troll items and refuses to communicate with the team. Sometimes, even two in the same game. They always seem to be on my team. Whenever somebody presses the leave button or exits out of League, they should be penalized and the losing team get a loss prevented and the ability to surrender early. It's not fair to people like me who just want to play the game, have fun, get better, and climb elo. Please for the love of everything that is beautiful in this world, Riot, find a better way to deal with this. I hate not being able to win in solo queue because of someone else not cooperating.