I'm sure that a lot of these ladies later on realize that the life of a sex worker is far from the glamorous portrayal they might have had before signing up, but that doesn't mean they were trapped.
While some of us mongers are respectful and comfortable to work with, there are also some assholes, head cases, and some certifiable sociopaths. And, they all write reviews here.
Not every AMP lady ends her day with glorious feelings of satisfaction beyond the knowledge that money has been made. As you point out, the money is far better than what they could make back home, and far better than the menial jobs many could secure here with limited language/cultural skills.
I met at least one provider who must have become enthralled by the "glamour" and promise of riches, but she had no business being in the business. Didn't want to be touched, didn't want to have any oral contact, and seemed ready to steel herself to survive intercourse. Not much different from my first wife ;-) (and I was paying for this?????). I don't think anyone would consider her trafficked, but she still should not have become a spa girl.
There must be some venues that involve human trafficking, but I suspect it represents a tiny sliver of the activity in DE, PA, NJ, MD, etc. Many are ambitious young women who will be in the life for a few years to make a stake and then transition to the straight world, many others are middle-aged women, often single or divorced mothers, trying to support a family and stay one step ahead of deadbeat dads and abusive ex-husbands or boyfriends.
It's just that crying "human trafficking" solves the question of why spa work must be crushed, since the moral arguments are stale and don't survive scrutiny, let alone warrant significant attention by law enforcement.
My $0.02