TL;DR - The article shows a clear view of the towers collapsing and claims that this confirms that it was not not brought down by explosives.

Strawman:

In fact, in ordinary controlled demolitions, engineers identify the primary supports, often on multiple floors, to assure that the building collapses inward.

Disproving the Strawman:

The video in question shows in close-up where the building buckles, not at the base, but at the point of impact around the 77th floor.

Conclusion:

Since the strawman (ordinary controlled demolitions place the explosives at the base of the building) and the video showed the initial explosion at the point of impact, it cannot be because of explosives.

Problems with the argument:

1. Even if we were to accept that in ordinary controlled demolitions the explosives are placed at the base, it is possible in this particular case the explosions were start at the top for obvious reasons, and hence cannot be used to rule out the theory of explosives altogether.

2. When the first collapse happens the camera is zoomed so we cannot see what happened beyond that area. However during the second collapse the camera is zoomed out and we can see that while the explosion starts at the point of impact, it sequentially keeps exploding incrementally downwards (start at 5:30) which, to me, further confirms the fact that explosives were used.

And final point: The camera zooms in exactly at the site of the impact point of the first collapse. Start at 00:30 - you see both the towers in sight. Then at around 00:38 the viewpoint suddenly jumps exactly where the first collapse starts, just 5 seconds before the tower collapses.

After that you can see someone setting up the camera for zooming out and they capture the second collapse with the full building in view. I can safely take a bet that these were no accidental tourists.