Yes!!! :dance:I see where you're shimmying, Cathy!
IMHO, it's leftover male-chauvinism. Women are designed for the pleasure and convenience of heterosexual men, visually or otherwise. When they perform publicly, it's mostly, if not wholly, for the pleasure of heterosexual men. This is so ingrained I think many people don't even question it.
It's more overt in communities where women aren't respected as equals and presumed to be always competing for the favors of heterosexual men who are expected to make more money and be more powerful.
Combine that with the ancient attitude that performing artists aren't quite high-class, because often suspected of looser morals and freer thinking than conventional nonartist folks -- and you got bias.
Doesn't matter what country it is, you can see it everywhere. But at least where women have insisted on presenting belly dance as an art you see pushback on the bias.
It seems there is often a political motivation behind that word "purpose," at least when applied to art or culture.