Why is the ranking system absolute garbage?

Just as the title reads, why is the ranking system so garbage? Especially to bronze and silver players, i'm finding it impossible to win a single ranked game in bronze ELO. Not because i'm bad or anything its because some one on my team always disconnects or leaves on purpose, or even worse feeds intentionally. This is a very common consistency in this ELO, half my team will be doing fine and one or even two of the guys on my team will be 0/6/0. Why do i keep getting paired up with these players.. it doesn't make sense. This division isn't even hard, i'm carrying my lane every game but i can only do so much in a team based game. They need to fix how teams are assembled, they should put players who have a similar win ratio with other players who have a similar win ratio. don't keep pairing me up with players who go negative every game just because they online and in the same division as me...