I don't know; I'm more concerned with the johns hiding behind their hypothetical skirts.
The authors at http://www.feministcurrent.com/?s=prostitution would universally guffaw at your misdirection towards religion. This is about patriarchal oppression of women, all gussied up in the same neoliberal language that has proven itself unmeritorious in other public spheres.
So as a gay man, it would be highly immoral for me to have sex with a prostitute whom is a bottom, but renting the services of a top for the night would be totally fine. Am I interpreting you correctly (not that I have, or plan on, engaging the services of sex workers. Not really my scene.)?