To the best of my knowledge, the Censure Carter effort is still under way. I ran a cursory Google search and didn't find anything indicating otherwise.
So if you've heard that they can't censure the peanut-brain, it's probably your 2nd possibility --- leftoons trying to throw wrenches into the works.
For what it's worth, I signed the petition. But again, this was another effort where execution left a lot to be desired. I watched the ad, hoping to see something really compelling. What I saw was an ad that made little sense unless you already knew some of the history behind it.
IMHO, they'd be a lot better off getting a group of media-savvy Freepers and other conservatives together to screen these things before sending them out for mass consumption. But then, that might lead to campaigns that were actually effective...
Followup...
I still haven't heard back from the folks at MAF. Not even a "thank you for expressing your concern," let alone an "Oh, crap --- we sure screwed up" message.
Must be nice to have such high self-esteem that you can ignore perfectly valid criticism.
(And for those of you wondering, the answer is yes. I have indeed made some phenomenally boneheaded mistakes in the past. And yes, I've owned up to them -- and learned from them -- as well.)