From my personal experience with Moony, he's not malicious or incompetent. The issue with Moony is that he unintentionally pushes people around on accident. I know that sounds weird, but let me explain.
Moony himself is not actually a bad guy and he's not out to hurt anyone. The problem is that when Moony wants something, he makes it known. He won't really push the subject, but you can tell when he wants something. The issue is that with the meek persona he has, he kinda draws sympathy from those who aren't directly involved in any conflict he is involved with and often times they view him as being bullied by people. Moony in turn just says that "It's okay" and tries to withdraw, but then people back him up and push for that thing he wants and more or less get it for him. It's a very strange phenomenon, and I don't feel that Moony actually does this on purpose, it's just the usual way this sort of thing plays out.
People who are attacked by the mob that forms to 'defend' Moony often see him as manipulating people to get what he wants but I don't think he actually is. I don't think it's his intent at all, it's just the natural reaction of humans to try and defend the 'weak', in this case the shy, quiet and meek persona Moony has, that causes them to rally to his 'defense' and force people to do what he says. One of the big issues is that Moony doesn't handle conflict very well so if he ever does something and he is at fault in some way, he will vehemently deny it, not because he feels he can 'get away with it', but because I think he just wants to pretend that the conflict will go away if he just says it never happened, which of course just pisses off people more when they feel they've been wronged.