This is an interesting analogy. I do get the sense that many waitresses and waiters hate their job, and do it because of lack of other options. However I do feel that by using their services and paying them, I'm helping them. They've made this choice, under a certain amount of coercion from the circumstances and system (which most of us suffer from to some degree, working because we have to), but my helping them get paid is helping them. I do find it important to be nice to them and treat them as real people, even moreso than people with whom my interaction is on a more equal footing.

However there is nuance here in matters of degree. I think I can tell when a place treats their staff well or shittily--it tends to slow in their attitude. I prefer not to patronize a place when I get that shitty vibe.

It's interesting to think about how this translates to sex work. If I used such services, I would want to feel like the person I paid somewhat enjoyed her job.