I don't think this is a problem at all. It's a strategy that pretty much any competitive game has; attack the weakest link. Why fight against the good players if you don't have to?
It's no different than playing Call of Duty and consistently killing the weak players so you can get killstreaks to use on good players.
You even see something similar in action games & RPG's too. Do you take on the tougher opponents head on and make things harder for yourself? Or do you take on the weaker enemies first to make yourself stronger, therefore making those tougher bosses easier?
i dont think its a big problem, its mainly actually for stock mode, any other gamemode its fine i think if you imagine the same thing in other games, doing damage to someone doesnt make you able to kill someone else, and in stock where dying is a big deal, thats the problem
however i would love to see this strategy in motion, i love strategy and i think its what makes a game