I remember seeing the NOVA program how the towers fell, which covers the outside support vertical structure AND the inside vertical structure.
One rather unique feature to the WTC buildings was that the outer and inner structure allowed the floor beams to be rather long and supported, like bridges at either end. What this also means is that BOTH ends must be supported, the outer structure is as important as the inner structure. It is impossible for the floor beams to exist supported at one end ONLY.
In any case, the progress of the flaming jet debris took out a large section of both outer and inner supports, also stripping much insulation from around the supports, making them more vulnerable to the heat of the fire that ultimately weakened the vertical support structure critically.

So, there is no denial in this publicly aired TV show of any part of the WTC structure.
It is obvious that the inner structure alone would not support the floors without outer structure to hold up the other end of the beams, that kind of structure would be called 'cantilevered' and this was not.
The heat of the fire weakened enough of the metal in the impacted area to allow the top part of the building to collapse as a pile driver onto the rest and start a cascade of pancaking floors.

(This is also where some of the folks who claim the towers collapsed too fast for physics. they are ignoring the fact that the collapse started not from the top but from the weakened area).

And finally, about a month after the coalition went into Afghanistan they recovered a tape of Osama taking full credit for the deed, and telling his buds that the total collapse of the structures was something they hoped for but it was mostly a lucky, forgive me, 'break'.