Are you for real???
The flight plan was approved by Malaysian Airlines and it shifted a little north to avoid a storm.
BTW how high were those Ukrainian planes flying when shot down???
I doubt they were at 33,000 feet or even close.
As Mashood noted above, a UAF AN-26 was shot down at 26,000 feet. It would not be unreasonable for the separatists to suspect that a UAF was flying higher to avoid a similar fate. And if most other civil aviation was already avoiding the area, it might not be so unreasonable for them to suspect it was a UAF transport.