I'm not saying they do help with the game, I'm just pointing out why they do what they do. Personally, I think there should be more protection for lower skilled players, and that's where something like skill based matchmaking should come in. Unfortunately, there are ways around such things, really it would make more sense if they had a system where you could report players that are clearly above their skill level. Rather than ban them they should be able to analyse them and determine if they are where they should be.
Systems like that take time, money, and probably man power to create so it's unlikely something that will happen. People in all games are affected by smurfs and the like, it's another side effect of their super cranked up matchmaking methods. Hopefully they do find some way to combat it though, as it kills the game. Personally, I find easily winning against worse players really boring most of the time, it wasn't fun when I was going up through rivals, it's boring as everyone just quits. I really don't get how people do it and enjoy doing such a thing.