I thought about your human empathy v culture remark. It is true, empathy is a human trait, however, each culture and society have unique mores of their own. These idiosyncrasies will miss, or emphasize, various aspects of personality en masse, to some extent; evidently, there are different cultures. So maybe in this case, those belly pokers have been indoctrinated to be less empathetic towards what they see as overweight.