I think this is just another symptom of their general illness. Any time a "truther" does anything that a normal human being would be ashamed of, the rest of them simply eject them from the flock - "We don't need to apologize for him - he's a disinfo agent!" It gives them the perfect out to allow truthers to make up any nonsense they want, while still thinking that they are "the good guys". Essentially, they pretend that it is we who are doing all these awful things. Look at some of their threads about the recent activities in NYC - any time anyone there did anything really odd, he was labelled a "JFER", or some other misspelling of JREF.
It never seems to occur to them that at some point, almost everyone in their movement has been disowned as a "disinfo agent", and that, if everyone in their movement at some time does or says something outrageous, then maybe, just possibly, it really is their movement that's doing these things.