You're not dragging others down if they're placed at the same rank with you. They dragged themselves down there.
Also as Jessicka pointed out, you can easily stick to 2-3 characters, especially if they're a support or tank since people are generally glad to have them.
That being said, I can only wait to see if this starts banning people for playing Mercy. Then I would say that's proof this system is busted. If the guy in the OP intentionally did it, then it's his fault.