Yeah, de-whitelisting mutators is one thing... I may not really approve of that, but it's your game, whatever... but the fact that this broke all the servers that did run them for whatever reasons, however legitimate... and moreover, that nobody was notified of it, and no mention was even made in the changelog or mutator whitelist thread of removing them, is seriously un-cool. I wasted a LOT of my scarce free time trying to track down why my servers weren't working, and a lot of my players are still very unhappy and blaming me for all of this.
EDIT: I should also point out my reasons for my disapproval, I think:
Firstly, I would much rather new players grind up on poundamonium servers than on, say, suicidal servers, where the other players really don't want to look after a bunch of lvl 0s. I've had NUMEROUS complaints about this happening lately, and I never used to. I really don't have time to baby-sit my servers and kick low-level players.
Secondly, I really don't see the problem with people using mutators to level faster, especially if they increase the relative difficulty, as the poundamonium ones do. Not everyone wants to spend assloads of time grinding up against weaker enemies, so power-leveling is a valid strategy, IMO. Especially since some people, like myself, very very seriously dislike leveling systems with dragged-out grinding like that, but whatever, it's a personal preference--I just find it harder to recommend the game to people when there's absolutely no way around the long grind. And yes, I've bought AT LEAST 10 copies for friends so far in the past, so I'm not just blowing smoke out my ***.
Third, in the time since the update, people have only been playing on broken maps and using exploits, probably because without perks, they can't reasonably survive with just a pistol. This is an issue with it being broken more than anything, but regardless, it's lame.