It should be obvious with the number of Ukrainian military aircraft that have been shot down by the Russian mercenaries, the latest incident was a deliberate shoot down with unintended consequences. Their posts on the internet, now deleted, show they thought it was a military transport. Once they checked the debris at the crash site, it was obvious it was civilian and they reported to their controller that there was no military material.
It wouldn’t surprise me if the Donetskian knumbskull Igors pushed the red button thinking that it was a Ukrainian transport plane while the Russian technicians operating it under Putin’s orders knew very well that it was a commercial airliner.