Jim Carrey took to his Twitter account - where he has in the past blamed vaccines for autism! - to deliver a message about Kick -Ass 2, and how he won't be supporting it with publicity.
So he doesn't think the film is bad, it's just that post-Sandy Hook - and post his own newly extreme stance on gun control - he can't lend his face to the pre-release publicity campaigns (which are probably beginning right now for long lead press).
That's... totally reasonable.
Look, I don't think violent media causes violence in the real world, but what happened at Sandy Hook - and the FIVE THOUSAND gun deaths in America since - has impacted Carrey enormously. Since he never made particularly violent films this likely won't cause him to choose future roles that differently, but he's putting his morals where his mouth is right now. I respect the hell out of that.
And I wonder if the studio is breathing a sigh of relief. After all, with Carrey's anti-gun stance many of his interviews will likely turn into discussions of violence in film and he would likely make the sorts of broad anti-gun comments that make gun nuts threaten to boycott stuff (just like they seem to have boycotted education and toothpaste).
I have shot guns - pistols, shotguns and machine guns - and I love doing it. It's fun! But just because it's fun doesn't mean I think that these weapons should be freely available. All respect to Jim Carrey for fighting the good fight.