Very interesting subject. My ideas are different (whose aren't?). I think a person who is in tune with God/Spirituality/whatever is not all that interested in what is termed as "immoral sex", loves their partner (if they have one) with no interest in screwing around on them, and has little or no need to satisfy themselves physically with prostitutes, girl/boy friends, whatever. They are already fulfilled as a spiritual being in a human form. As we all know sex is not much different than a drugs, alcohol, extreme sports such as bungie jumping to "feel alive", or other crazy things many folks to enhance their emotional feelings.
As for prostitutes I am not sure when it comes to those who use others for their own benefit knowing that "John" may be married to enhance their budget, or to steal from their wallets while they sleep, etc. But I AM sure that a woman, in Sudan let's say, who has NO other way to feed her children and survive other than by selling sex, and possibly knows of nothing else due to logistical circumstances, cannot really be held as a "sinner" IMO. I mean if you live in Africa, your husband has been killed, you have 3 kids and are starving....what else can you do?
To expound more on the above, what if a girl (or boy) is raised by a prostitute who trains them to do just that? Poor kid has no other thing they know in life as a means of living.
As for the "don't do this or you'll grow hair on your palms" thing....well....it's better than going to a prostitute and spending money and taking chance on a disease a pill doesn't cure.
We are to judge ourselves I'm to understand. So our reasons for what we do will be our own issue to judge before a Holy God/Supreme Being in the end. "Nuff said.