Think a second about the meaning of "free fall". Free fall velocity is the speed an object falls to earth in the absence of any upward force aside from air friction. In other words, a penny dropped from a height will reach "free fall velocity" which is the velocity which balances the force of gravity (downward) and the force of air friction (upward).

The reason this makes no sense in the context of an intact building falling is that there are significant upward forces being exerted against the top section falling downward. Every time a floor hits the floor below it, there is a counteracting force moving upward into the falling piece, slowing it down. It might still continue to fall, but it would not be able to do so at anything remotely approaching free fall.

The only way you could approach free fall velocity is if there is nothing counteracting gravity aside from air friction. In other words, where did all the upward forces that are exerted by the frame of the building (how buildings stand up in the first place) go? What happened to the steel beams to allow the collapse to occur so rapidly? The forces involved from the airplane impacts followed simply by gravity are not remotely sufficient to explain the collapse as witnessed.

That's the problem.