No oxygen? The planes blew all the windows out of several floors near where they impacted. The jet fuel burning didn’t do anything good for the concrete on those floors. The steel didn’t have to melt it just had to lose it’s elasticity and some of it’s strength. Oh, and jet engines are not made out of common steel, they have special high temperature alloys of exotic metals precisely because steel can’t handle that type of environment. If one part of the support loses it’s strength and the weight of the upper part of the building deforms it more stress is placed on the remaining columns, which are also weakened. Like a chain, once the weakest link is broken the collapse starts. The intact upper floors acted like a wedge and a plunger forcing a high pressure wave downward as they fell. The mass spread the building and the air pressure continued the destruction. Beams were shot out of those buidings into every surrounding building during the collapse. A lot of that damage isn’t included in this flake’s assertions because it doesn’t back his half baked theory. The simplest theory is probably the most correct and his is so well choreographed and would have involved so many people a leak is inevitable. People do talk and the more people involved the more the liklihood one will feel guilty and spill the beans.