I long ago stopped trying to actually reason with Truthers, because basically it seemed I had said everything I had to say, and it appeared to make zero impact anyway. So instead I eventually adopted my present persona of semi-articulate doofus. But for some reason, the OP has called me back. So what the hey, let's give logic at least one more whirl.
Let' look at this thing one step at a time. Silverstein said "pull it," which some Truthers take as an industry term for demolishing a building. But even the most die-hard Truther would likely admit (however begrudgingly) that the word "pull" has other meanings beyond demolition, which could be applicable in this context -- "pull out" or "pull back" just to name a couple off the top of my head. Had Silverstein said something more specific like "bring it down" or "blow it up" or "set off the charges now," there would be a lot stronger case here. But he didn't. So at best, Silverstein's words are ambiguous, and open for interpretation -- and thus prove nothing.
But let's say you're one of those people convinced that "pull it" in this instance can mean nothing other than "demolish the building." OK, fine. You now have to explain why Silverstein would openly admit such a thing on television. A momentary lapse in judgement? A slip of the tongue? What, exactly would have possibly possessed Silverstein -- on this one occasion and one occasion only -- to admit complicity in mass murder? So now Truthers have two things to explain: why "pull it" can only mean "demolish it" despite all the other possible meanings, and why Silverstein would actually publically confess this one time.
But let's say you somehow get past those two things. Now you have to explain whether or not WTC7 was in fact a controlled demolision. After all, video evidence and eyewitness testimony abundantly indicate that the building was badly damaged by falling debris, and burned out of control for hours. The vast majority of experts find nothing at all unexpected about the collapse. They are comfortable with the fact the building fell solely because the structural and fire damage it sustained, with no need to invoke a CD to bring it down. So how do you explain why there's no evidence at all that WTC7 was a CD, irrespective of what Silverstein may or may not have meant in his one unguarded moment?
Ah, but it doesn't stop there. If indeed the building was wired for demolition, how the devil did the explosives not go off prematurely, while an uncontrolled conflagration raged away all around them for hours?
But wait, there's more. Now you have to explain why anyone would demolish WTC7. After all, its two vastly more high-profile neighbors had already been destroyed, with spectacular effect. Why, just for good measure, bring down a building that no one had ever heard about? Some have suggested it was to destroy sensitive records, in which case you have to explan why they didn't simply use paper shredders, which not only would have been a lot easier but would also have been far more effective.
So let's sum this up: To believe that Silverstein's comments in any way support the Truther movement, you have to explain why a couple of highly ambiguous words can in this case have only one very uncommon meaning, why the person uttering them is publically confessing to mass murder, why there's no other evidence at all a CD actually took place, how the explosives waited patiently for hours within the inferno until Silverstein gave the magic order, and why anyone would even bother to blow up the building in the first place.
That a college professor could possibly have navigated through those questions and still somehow concluded Silverstein is stating WTC7 was a CD speaks very, very badly of that professor's judgement and reason. And I don't think there's anything at all ad hominem about that last statement.