I also saw the programme and there are two other points mentioned that might be germain to this discussion:
- The civ a/c departed 30 mins (I think) behind schedule. When the Vincennes looked at the civ flight schedules, no a/c should have been there at that time. This became another small piece of the jigsaw building to the supposition that it was hostile.
- The departing field is a mixed Civ + Mil. It appears that, the Vincennes radar op picked up a mil a/c on the ground and - through a mishandling of the roller ball (similar to computer mouse) held the mil a/c and this ID was confused with the civ a/c that then took off and was monitored.
In other words, like all disasters, this was a classic Swiss Cheese.