That was my thought too, I found this story to be really depressing.
But I feel like the author is trying to present this as a general and wide-adopted trend when it's probably quite marginal.
It's also different from other (consensual or non-consensual) activities because it's sex; the same way that it's different from playing frisbee or (relating to the sibling comment) fixing a car; let's call this the dimension of intimacy.
So in binary terms, we have four quadrants, with prototypical examples of playing frisbee (non-coerced, non-intimate), forcing someone to fix a car (coerced, non-intimate), prostitution (non-coerced, intimate), rape (coerced, intimate).
I hasten to add that prostitution is often, in fact, very clearly coerced (by threat of violence), and of course there's an argument to be made that many other instances are also coerced (by threat of poverty).
Edit: Re-reading my comment, calling it misleading and bizzare seems unkind, I apologize. Thinking in terms of these two dimension is (I think) helpful, but it's also an arbitrary choice. When you choose other (or fewer) "variables", the point made in the article follows.
Someone purposely pushing someone over a cliff is not the same as someone running out of water in the middle of a trek across a desert because the oasis they expected had run dry.
The point is that there's a difference between regular labor and sex.
It's about stating a difference because sex work being seen a mainstream practice is arguably not a good thing. (be it legal or not, that's not related here)
But whatever, clearly there's a group of people here on HN who are taking the hard line "sex work is just labor" position and there's not going to be a rational discussion here.
Losing 10% of your net worth and losing 90% of your net worth are both traumatic. One is more so because it's to a larger degree, but it's not an entirely different thing, it's just a different amount. That's why we have different punishments for petty theft and grand larceny. Not because they're completely different crimes, but because they're different degrees of the same crime.
This is not to say that I am completely comfortable with this thing, though. For someone like myself, this Sugar-daddy-baby thing feels like a 180 degree departure from the values that I grew up with, which society itself promoted as the right thing. Now I just feel lost and alone. Everything is depressingly transactional. In all honesty, I'm quite comfortable with that when it comes to most of my daily interactions. But when it comes to relationships, I feel shocked. Maybe I'm a hypocrite.