I've just got to ask. What evidence says those 45-degree cuts weren't done after the fact? It would be rather bold to think the FD wouldn't be going apeshit about it, if those angles appeared that way untouched post-disaster.
None. In fact pictures prove that the cuts were done after the collapse, when they were dismantle the pile of rubbish after the collapse to find bodies. Don't tell anybody, it is a secret, but after the biggest collapse of the history of mankind, those columns which were cut, were complete dustless. After the catastrophe, after bunch of collapsed buildings which covered whole manhattan under the inches of dust, those columns were squeaky-clean. It makes me wonder...

And if I remember correct, there is even a picture with a wider point of view, where you actually see guys doing these cuts, so it is safe to say that the claim is just another piece of foil hat bullshit. They used acetylene torches and thermal lances to do that work, and those lances could be by far the best explanation to the finds of Niels Harrit, because they use similar fuel than so called thermite.