So I skimmed over the link you posted. Is this guy saying that they fell because of the fire or that they fell unrealistically?
If you think they fell because the planes hit them or because of fire, what flavor is the kool-aid?
If you understand basic metallurgy and physics, it does make sense. When you weaken the metal support structures with the 1500+ dgr. temps and put 1,000s of tons of weight on top of it, well, you know what happens.
As far as conspiracy's... I suspect some, but believe none fully.