No, it's supported by physics. However it's a little hard to convey. There's the problem of scale again.
I know I keep mentioning scale, but it seeming increasingly obvious that this is the one concept I'm failing to communicate here.
Large objects are physically different to smaller versions of the same object. If you scaled WTC7 down so it was only two feet high, then yet, you could just knock it over. But as you increase the scale, then the structure is increasingly unable to support its own weight in anything other than a perfectly straight configuration.
Consider what you happen if you were to magically lift up WTC7, and place it on a corner. What do you think would happen?