I can see the argument that sex work is coercive through the logic that all work is, to some extent, coercive. But the solution there is to remove the coercive pressure of work, not to prohibit sex work specifically.
I don't think it's a stretch to say that work that requires that one's sensitive orifices be penetrated is more "coercive" than work that... doesn't make such demands. Mind you, there are things that qualify as "sex work" which don't involve that (massage parlors, cam shows, etc.); and at the end of the day it's a situation where legalization and regulation for health and workplace safety/dignity seems obviously the least bad solution. But there are qualitative differences all the same, which indicate that regulation should be different (and stronger) than in some other industries.
(EDIT: God, I realize that the clinical tone I just took is super cringeworthy, but I'm not sure how better to phrase it and don't want to spend any more time mulling it over. Oh well.)