I don't agree with punishing players. Beyond the achievement requirements, no mentor agreed to help their fellow players, nor are they obligated to be a paragon of virtue that other players should aspire to. It is just another achievement with an new roullete that helps to alleviate Duty Finder queues.

The real issue is that the player community wants to make it more than what it is. If you want a real mentoring system. You should probably get rid of the rewards and build a system the requires actual time and effort by would be mentors.