*Disclaimer- I did not read the entire thread, I'm just answering the OP's question with my comedic opinion
A- If they can fuck some of the dudes they gotta fuck for money (although we all know they are paid for the TIME they spend with clients, anything that happens during that time is between consenting adults), well then... they can fuck ANYTHING, so y'know... women too.
B- Marketing (I'm sure someone in this thread somewhere has already posted a perfectly fine, nuanced explanation about why it is good marketing so I'll just refrain from doing so.)