If it was brought down by a SAM, it had to have been intentional. These things don't happen by accident in Iran any more than they could ever happen in the US by accident.
If intentional, it could only have been because it was hijacked or cyber-jacked. No nation would slit its own political and economic throat by exploding a jet full of its own people, and putting its entire airline industry at risk.
Support for a hijack/cyber-jack - rendering a SAM merely a response, not a cause - is found by extending eastward the straight line from [point of last FR24 contact] to [point of impact]. Even if one allows space (1km?) for a right turn, we see that PS752 was in fact headed straight for downtown Tehran. If that's where it was headed, a SAM shoot-down finally makes sense: to protect the seat of Iranian power.
Any other SAM theory is so absurd, it's sad.
Last edited by Wind_Tunnel; 11th Jan 2020 at 00:13.
Reason: typo