I have sold drugs in the past, doesn't bother me a bit selling a junkie his fix. I quit because I got tired of getting harassed by cops, and other factors.
I don't pimp out runaway teenage girls because pimping isn't my chosen profession, but if it was, I'd do it and sleep soundly at night. And for the most part yes, its the law that "holds me back" from doing a lot of things. If I'm in jail it hurts my long-term ability to profit, so it makes better sense to make money within the limits of the law.
My point was that if you put the "morals and ethics" microscope on any money making venture can find something "morally and ethically" wrong by traditional Judeo-Christian ethics (which most of us are taught from birth, and drilled into us). Morals are subjective to the person. I was taught it is morally wrong to not try and earn a profit where there is a viable, paying market. Its their duty to protect themselves, not mine. Caveat Emptor.