One plane could be believed to be an accident / inconclusive. So you crashed one plane, that's not getting you much.
Many planes would ... what? Again you don't get much if you crash a bunch of cargo planes, even passenger planes. It would be destructive and disruptive and horrible, but not crippling to any nation. The scale of being a pariah nation would just increase. What do you get out of that if you're Russia?
It seems more like something a smaller terrorist org would do, or a messed up cult.