As always, context is everything. Jowenko was the victim of a planned piece of deception by truthers. Initially, he was interviewed on a program discussing the collapses of the Twin Towers, and pointed out that (a) their collapses initiated at the areas where the planes had hit, rather than at the bases which is the way controlled demolitions are normally done, and (b) if charges had been placed in the areas where the planes hit they would have been set off by the fires much sooner. He concluded that the Twin Towers collapsed as a result of the airliner impacts, and that no explosives were involved, an opinion which he has never attempted to retract. A group of truthers then showed him a video of WTC7 without a sound track - so he wouldn't notice the absence of the sound of explosions - and without any information about the size or location of the building, and he was duly fooled into believing it was a controlled demolition. He has since expressed serious confusion about how WTC7 could possibly have been rigged for demolition in the time available, but sticks to his original opinion.
What we can deduce from this is that: (a) it's possible to fool an expert, from a restricted view of the WTC7 collapse with the sound track removed, into thinking it was a controlled demolition, and (b) Danny Jowenko has difficulty in changing his mind, even though he knows his opinion doesn't make sense.
Oh, and that truthers are lying scumbags who try to mislead people and pretend it's done to seek the truth. But we already knew that.
Dave