You have to ask what percentage of people outside of US believe this. And it is a very substantial one. Outside of the US there is no "gag" order on this in the media and people discuss the possibility very openly. NO NEWS OUTLET in the US covered the story that dutch scientists found nanothermite in the ruins of WTC. If you want to believe that steel skeleton structures that never fell from fire before 9/11 would fall perfectly and neatly onto their foundations at near free fall speed in 2 hours or less and one building would fall that was never hit by anything be my guest. It is Reichstag fire ver 2.0.
I don't know if any of the claims made by the 911 truthers are in fact true. But I see no reason to boycott a station because they are willing to let someone advertise a point of view that some want to see suppressed.