a controlled flight into ground, thats all. surely no "help" from the russians to bring it down, no artificial fog, no bomb on board.
It was not a normal flight where rules could be followed because:
1. It was a political mission to rub history to the bad Russkies. Therefore, all advice from the ATC's was suspect and subject to political interpretation by politicians who previously frequently insisted that it is them and not the pilots who have final say on everything.
2. The "Main Passenger" previously got rid of competent, experienced pilots after they refused to let politics override commonly accepted aviation procedures. The pilots at helm pretty much had no training and no qualifications to fly that plane, certainly not in these conditions and the only reason they were formally given that job was because there was nobody qualified left after the competent ones where "reassigned"
That's the core reason for the crash but if anybody brings it up the fanatics scream that this is politics. Well - it was from the beginning and it still is.