I've noticed two ways that the media use the term "truther," which of course blurs the distinction between them.
The first, the sense familiar in this forum, is disputing the sequence of physical events on Sept. 11 that ended with the complete or partial destruction of several buildings and at least one airliner. I don't have to name names here.
The second refers to people who, regardless of their views on the first issue, believe that the government has not examined the right political questions regarding the events: what caused it, how it could have been prevented, whether the policies of the last 10 years have had the intended result.
Whenever I catch CNN in a waiting room somewhere I can always count on them to say something completely disgraceful. Last time it was Ray McGovern being hauled out of Hillary Clinton's speech for standing up. CNN reported, very snobbishly and dismissively, that he was a truther. As far as I can tell his "truther" activities are limited to the second sense, although he has associated with truthers in the first sense. (Politics makes strange bedfellows as always.) CNN spent about 20 seconds on that report, then spent several minutes hawking a new battlefield robot that didn't work on the set.
Maybe there are people who are OK painting political debate and make-believe games with the same brush, but I'm not one of them.