It is also quite as possible for someone with several accounts to give someone else a huge merit reward simply because they want negative action taken against that person.
Did you even read the posts? Evidently not. The user who gave +50 positively declared that he was a friend of the other user. The user who got +50, got it for a post complaining about how very unjust it was that he needed 150 merit to rank up. Why are you positing in this thread some hypothetical scenario which is so clearly inapplicable in this case?
I am not saying this is happening here,
No, you are doing the sleazier equivalent: You are insinuating it while avoiding saying so outright. Otherwise, you would have no logical reason to post in this thread.