So no single term, for something so widespread, must be taboo to talk about, or too risky to address, and threaten the social status of someone connected to the uglier side of a profession.
Of course I didn’t “single out” anyone, but you got that.
Why single out sex workers here? I understand the other examples, but unless you're talking about sex workers tricking people/robbing them or something else, it seems like a service-profession like any other, like a cleaner or what not, but I'm guessing you wouldn't actually put 'Actual mercenaries and cleaners kinda fall under the “all is fair in love and war” frame'.
I think a mix match of perverse incentives, rent-seeking, cobra effect, regulatory capture and institutional corruption all together lead to the inevitable situation of institutions or professions whose incentives depend on the persistence (or even worsening of) the problem it claims to solve.