This doesn’t dismiss the moral issues with it, though.

Genuine question, what are those?

I recognize issues with large power imbalance, such as huge gap in maturity, roles (e.g.: student/teacher, worker/boss), intelligence (severe mental disability on one side), etc. where one party could easily coerce the other into something, possibly even unintentionally (e.g.: one party wants something and is already upset, the other party is worried about not only breaking up, but also getting fired and not being able to afford rent, thus pushing through).

But in this case, if the above doesn’t apply, what are the other problems?