Eh, I think it's a bit more complicated than that. The guy could have easily got himself a * in any number of ways that he could be pretty damn certain weren't tied to human trafficking, but instead he went to some place called "Orchids of Asia" spa to get serviced by women who spoke zero English. There's enough red flags that if it somehow didn't click with him that he was likely supporting human trafficking, it could only be because he basically didn't care enough to notice what was staring him right in the face.
And I do get your point here, that you could make similar arguments that people who eat meat are supporting animal cruelty, or people who bought weed prior to a couple years ago were supporting cartel violence, or people who wear Nikes are supporting sweatshop conditions, but this seems meaningfully different in ways I'm having a bit of trouble articulating. Maybe because there were a bunch of alternatives available, maybe because of direct proximity to the crime, maybe because sex trafficking is even more messed up of a crime.