Because sleeping with a random bloke because they want to isn't the same as sleeping with a random bloke because they live in abject poverty & needs money.
If you can't tell the difference between the two then I doubt this conversation will be of much use.
It's not the same.
People care about who they have intercourse with (on average), people don't tend to have such reservations as to who they move objects for (be it bricks, plates or other manual labour jobs).
They are not comparable.
You have also not addressed my point, is it OK - in your opinion - for a rich man to go-to poverty ridden Africa & offer food to starving women in exchange for sex?.
By your logic it's exactly the same as going to Africa & offering 50 people jobs.
Or is it actually quite different?.