You may think 9/11 truthers are your average POV pushers. They are not. http://911research.wtc7.net/re911/wikipedia/index.html http://www.serendipity.li/wot/sft_wikipedia.htm
The founder of "Scholars for 9/11 Truth", Jim Fetzer has edited pages himself on Wikipedia, as do other key leaders of this movement. Most of the 9/11 truth movement consists of younger folks who spend time on Loose Change forums, some which have edited on Wikipedia. I've been on there to check it out, but you quickly get banned if you challenge their theories at all on the discussion forum. These are the people who come to Wikipedia to spread the truth, and nearly all are single purpose accounts with the one purpose of spreading the truth.
MONGO has taken more of the heat then myself, because I try to minimize discussing anything with them on the talk page unless it's absolutely necessary for working on the article. MONGO and others have carried the discussions more, and has dealt with some of the more difficult "truthers". Thus, he has become the target of trolls. Meanwhile, MONGO sticks around and edits other stuff, such as national parks articles, as do others who enforce policy. We don't suppress the "truth", but keep the articles consistent with WP:NPOV#Undue weight and WP:SUMMARY, but giving brief mention of the theories in the main articles and details in subarticles. There are quite a lot of articles about the truth movement, the people in it, some of their videos, etc. I definitely didn't come to Wikipedia to work on any of these articles, heck I didn't know much about the truth movement in the beginning, but not going to let the main Wikipedia articles on 9/11 to circumvent our policies and be used to spread the truth.
Yet, despite all their gripes about Wikipedia, it's amusing... I do see them reference Wikipedia articles very often on the Loose Change forum and their other sites. It's a challenge and very time consuming to maintain these articles. MONGO has been invaluable.
-Aude