A guess is a guess is a guess is a guess. It doesn't matter who is making the guess... it is still a guess. Your appeal to authority tells you that a guess from an, "expert," has more value than a guess from a layman. If an assertion is supported by nothing more than an assumption, than it must be viewed as equal, regardless of who is making it.
Trusses sagging is a guess. It cannot be proven with a scientific equation. Columns bowing is an assumption, it cannot be proven with a scientific equation. Therefore... these assertions hold no more water than a layman saying explosives brought down the towers. It's yer ego (elitist attitude) and prejudices that distort your viewpoint... by telling you that all opinions are not created equal.
NIST's report is a whitewash. None of the theories in it, can be proven with science. You cannot prove that trusses actually sagged on both towers, or that they (trusses) caused the outer columns to bow... or that this bowing caused all four sides on each tower to fail simultaneous... These are all guesses... based out of a cornucopia of scientific improbabilities.