To get to the only point, "truthers" is a label applied to those who claim Al Qaeda did not bring down the WTC on 9/11 and that the US gov't, under Bush, did. As most of the posts to your thread demonstrate, "truthers" is not a term to apply to any other conspiracy you choice.
To make it short, do you think there is no difference between the "truthers" making their 9/11 WTC claim and the "birther" demanding real proof of BHO's birth? Or did you use a misleading thread title?
The title of your thread demands your answer!