Because they're in a war with Russia, although not official, with the Russkies occasionally sending helicopters and jets across the border. One Ukrainian Jet, according to Ukrainians, was shot down by a Russkie Jet. These aircraft and Russkie drones also pinpoint Ukrainian positions so the Russkies can shoot missile sat them from Russian soil, which has been going on for awhile now.
So I’ll assume they have proof of previous incursions of Russian planes and were set up to take them on, so is it possible that a plane like the airliner could be mistaken for a warplane?
No, because the airline was flying at 33,000 feet and had flown all across Ukraine before flying over Russkie controlled territory. Furthermore, if the missile was Ukranian from where the Russkies claimed their SAMS were, then that means the missile would have had to travel over Russian controlled territory, all loud and bright, and yet not be noticed.
It is confirmed that the separatists had Buks in the immediate area. That they fled back to Russia. And the separatists were the first to know that something had been shot down, and took credit for it, before they removed their postings and started claiming they never even had Buks.
I’m still betting on the Ukes having botched this job.
Maybe you have an undiagnosed mental problem.
If the Russian government is sending planes and drones over the war zone then the Ukrainian forces both regular army and the oligarch financed mercenaries are doing a pitiful job of targeting. Are they really that bad? Any explanation for this poor performance?