@Xal0lex is the one responsible here, because out of all the posts you put in the list, he's the only one who gave merit to them.
You don't blame someone for being generous with pure intentions; those who took advantage of generosity are the ones to point fingers at.
Can't argue with that, though what I will say is that Xal0lex probably should've seen the pattern and not been so generous; it's not as if he's a newbie and hasn't seen all of the merit abuse and assorted shenanigans over the years.
On the other hand, this is just some questionable merit-giving we're talking about and even if it were blatant abuse, there's not much that anyone's going to do about it anyway. Theymos doesn't even care all that much about merit abuse (and I'm still waiting to hear his State-of-the-Merit-System address but am doubtful that it'll ever come).