He called Republicans "assholes." OK, fine. Not the best choice of words, but nothing I suspect LBJ didn't say.
But when you sign a petition saying that the US government was behind 9/11, you obviously have removed yourself from the status quo. Perhaps you are right. Probably you are not. But in any case you have put your stake in the ground and you have to accept the consequences. You want to be a radical? Fine -- more power to you. But don't think you can then be on the inside a few years later. If you really believe what you wrote, you have to believe you have the facts on your side and you have to have the guts to stick to your position when the going gets tough. Otherwise you shouldn't have signed the petition in the first place.
It'd be no different than if some Bush administration minion had once signed a petition calling for the return to the pre-Civil War south.
I don't see that there was any "smear campaign" against Jones. People merely reported what he had said and done. Now would be the perfect time for him to defend his position. Obviously, he can't. And that makes it objectionable.