you don't need to be an expert to know the simple thing that hot steel gets soft.
And when it gets soft and has half a building sitting on top of it, it can bend and deform, and once it starts to go, it runs away and comes apart.
Yes, I agree with you, the 9/11 "truthers" are nuts, right up there with the "we never went to the moon" nuts. :)
I can take it a step further... half a million people saw the planes hit the buildings, not on video, but in person, it was in fucking New York City. It isn't like it was a secret event. Further, one of my best friends was supposed to be on the AA plane that hit the tower, she swapped routes with her best friend a few days before because she had a family event to be at, otherwise she would be dead.
You can't cover up an event like that, too many people know too many people, same with the moon landings, someone would talk...
BTW, regarding the moon thing, I've met Gene Cernan (last man to walk on the moon) more than once in person, I had the chance to go to a lunch that he was a featured guest at and got to speak with him afterward, I don't for one second think he was lying to me about being on the moon.