It's a pretty big gray area. It's hard to pass judgment on them completely but also hard to excuse them.
It's true Meru could have flat out refused, and then she would have been sent out to work in the mines and her family would not have been fed. How do you separate out her own personal windfall from the situation, living in comfort while the rest of her people suffered, from the fact she was also helping her family? You could call her a collaborator because her complicity gave comfort and legitimacy to the invaders, but not quite as much a collaborator as that Bajoran guy who was rounding up attractive Bajoran women for the Cardassians.
Historically occupations end all the time. Occupying a foreign country is expensive. The moment you can't afford it you move on.
It is likely that Tora Naprem was also a not-so-quite-volunteer lover of Dukat. But to gain his ends, he could be very convincing and charming towards the Bajoran women. Problem was, once they fell into disgrace, he dropped them, looking for the next best attractive Bajoran female.