It was not the top. The fire was concentrated near the top. The infrastructure was severely compromised. What part of that do you not understand? The building was made to withstand an impact, not an impact and a fire of that intensity. If there had been just a gaping hole in the building, it would have continued standing. The structure would have remained intact enough to continue holding the floors beneath the impact. Given that the floors beneath the impact were damaged by the fire, it was nothing at all for the floors above it to continue putting pressure on the compromised structure until it collapsed.
Again, you are ignoring the fact that there is zero evidence for controlled demo beyond conjecture. There were no tell tale flashes or explosions. You can't hide explosions from that many cameras.
Again, you are ignoring the fact that there is zero evidence for controlled demo beyond conjecture. There were no tell tale flashes or explosions. You can't hide explosions from that many cameras.