“If it’s not Tznius, it’s not Tznius. We don’t have non-Jews sing or dance or parade around undressed for us. Nor do we have them do such things for women. If this is a non-Tznius activity, then why are we allowed to let a non-Jew do it for us?”
Many aspects of tznius don’t relate to non jews – e.g you are allowed to look at a non jewish lady whose hair is uncovered. And the nuances – are you against those who say that ladies skirts should be 4 inches below their knees even when that wouldn’t apply with regard to looking at non jews?
These arguments have no sense to them.