(mainly for americans)Why is it unpatriotic to ask questions about the 911 attacks?

There are so many discrepancies surrounding the events of September the 11th, questions that need to be addressed. I am not a conspiracy theorist, I do not go out looking for these discrepancies and I do not believe or disbelieve anything I read and hear. It's all propaganda after all, whether it's left wing or right wing. But it seems to me that many people are unwilling to confront these issues so as not to appear un-American. I've read so many comments on You Tube below the Loose Change film that I don't understand. Loads of people say we shouldn't question because that is attacking the memory of the people who died. But those people are the reason we should ask questions surely? The "Jersey Girls" tried to question the Government and nobody cared what they had to say (www.believeyourowneyes.com). I'm not attacking anyone here, I just don't understand. Maybe someone could shed some light on the matter.