That's because alot of people don't believe what the government tells them. And they shouldn't.
I saw alot of different works about 9/11. And some things stood out like how the dude who owned the buildings or whatever made out with 7 billion out of a 15-20 mil he started with. [insurance on his towers which he pulled the plug on a few of them which didnt even need to be brought down.]
And another bit which showed who all benefited from 9/11. All the bad guys blamed for it on the east on a scale of 0/10 scored a 0, where as a few select US Leaders benefited GREATLY from 9/11