What is up with matchmaking?!

So I'm a pretty chill kind of gal, don't care much for who I get as long as they know their stuff. Bronze adc that knows how to last hit and auto attack enemy champs? We gucci, I can keep them alive (usually). My major complaint here is... why am I getting people who are in their PROVISIONALS when I'm up for a rank promotion? This happens so often to me, it has me baffled. These kids are fresh out of leveling, get thrown in a game with me and several other people who are also trying to climb Satan's Ladder of Frustration and Feeders, only to get stuck with someone who barely has any comprehension whatsoever of the games mechanics or positioning.