Everything produces conspiracy theories. 9/11 was no exception; there are some who claim that the towers couldn't have collapsed just by the plane crashes and fires because it wasn't hot enough to melt the steel. They think explosives were used to assist the collapse.
It might be true that the steel didn't melt, in fact I doubt it did. But it didn't have to melt. Just heating it enough will weaken it, taking it below the strength the building was designed with. Once one structural member stops supporting weight (such as by getting destroyed by a plane cutting it in half) it puts more stress on others. Combine that with heat, the impact, and the very suddenly uneven load; and you're going to have a very unstable building.
As for the picture-perfect pancaking, that's just how it happens when you progressively stack greater and greater weights. Why didn't it tip? Because there was no reason for it to tip. Things don't just tip over; they get pushed over or the structures below is uneven.
Just because 9/11 was very convenient for some people in America doesn't mean they made it happen.
On a lighter, and late note, Happy 9/11. Yes, happy. Why should we not be happy? I don't mean barbecue and cheering happy, but perhaps content, going about our normal days. Not sad. Terrorists would prefer that you be sad and scared and haunted by what they did. Well fuck them.
P.S. Yay for old post dates screwing up order.