When we say prostitution is a scourge on society, we typically mean (without knowing it) that able-bodied people have better alternatives, ones that are more personally fulfilling, although, more emotionally involved and therefore more difficult. We also mean that we prefer a society in which sex results from mutual commitment rather than a purely financial exchange.
The whole issue is typically more complicated than we admit, especially since many of the harms we associate with prostitution result from its being illegal. But like I said, let's bracket that for now and concentrate on a small human population that may be unable to have mutually affectionate sex because they are physically disabled (not so far as to prevent sex, but just enough to make foreplay extremely difficult, if not impossible). Oxford University's Practical Ethics blog sets out some parameters:
(1) Many or most persons have a sexuality that generates strong needs for sexual relations, and
(2) Some disabled persons are partially or entirely incapable of satisfying this need except through the purchase of sexual services from a prostitute.
If these propositions are true, then it follows we might allow prostitution for the physically disabled. But what counts as disabled? That's a hard question. Many individuals suffer emotional or physical harm that makes having sex difficult, meaning that any obstacle to sexual relations could be construed as a disability. And it's borderline offensive to suggest that disabled persons are less sexually attractive than more able individuals. This leads Practical Ethics to conclude:
"Either the definition of disability is so narrow as to be unjustifiably arbitrary as a proxy for the real underlying moral issue, or it’s so broad as to include almost anyone. Why not — instead — just argue against a general prohibition, and let mature individuals decide for themselves (a) what kind of consensual sex they wish to engage in, and (b) in exchange for what."
Journalist and feminist activist Gloria Steinem, however, argues that prostitution is entirely negative: a symptom of addiction to masculinity and need for domination. "We need to eroticize equality," explains the noted feminist.