now that is an assumption.
no one said occams razor has any validity to it...Occam's razor states that the explanation of any phenomenon should make as few assumptions as possible, eliminating those that make no difference in the observable predictions of the explanatory hypothesis or theory.
again you seem to be missing the point here...Blaming the vicissitudes of global politics and economics on space aliens grossly defies that. After all, it is a MASSIVE assumption (in the lack of any viable empirical data on the subject) and it is an assumption that makes no difference to observable predictions with regards to human politics and economics.