She was goddess of love (in the sexual aspect of it) -- including having TONS of extra-marital affairs in the mythology.
And it's not about what she would really do as an occupation in order to make a buck, as if she was an actual person!
It's about the connection in people's minds that the goddess-of-(making)-love is also a kind of "patron saint" of prostitution, and perhaps the artist wanted to play with that image (if the theory in TFA holds).
Also have to know that prostitution itself wasn't a dirty, destitute, "crack-whore" style affair at the time, but something seen as a service to society, with some prostitutes more like columbines and geishas. Heck, they also had a kind of prostitution in the temples, as a sacred thing.
