Hardly, you are extrapolating first principles (ie something is unnatural) onto a second principle which is the interpretation or conclusion derived from first principles. The question of morality is not derived ipso facto it is contrary to natural purpose because as disabled person is using his hands when he lackes legs, it is a determination based on reason. Thus in the case of walking on hands your refutation hardly is applicable or even a refutation.
I'm sorry but I really haven't the slightest clue what you're going on about. Could you try it again in English?