I'm not entirely sure this reasoning makes sense. Take, for example, a politician that is only motivated to be in politics because he wants fame. Does this mean that none of his actions are politically motivated because his true motives are apolitical?
It seems to me that the act of choosing a political target, in and of itself, is a political motivation, as the political landscape has been the main informant of their decision.
I can see some merit to your argument, though, and perhaps I'm being overly focused on semantics?
FilthyHands