If they were real people, I would be fighting for their rights and freedoms in every way I could. That said, they are not, this scene shows how bad things were, how they are improving, and quite possibly, how much further they can improve thanks the MCs actions there.
Yes, they were not "in to it", just like I was not into most of the jobs I have been made to do, I have had to do some really disgusting shit, I didn't like it, and sure, I had a choice to quit and lose my income and home, but it was "in my best interest" to do it, so I had to stick it out until I found another job, where I could be treated poorly there as well. A whore isn't always into her clients either, but they do their job willingly, because it was the agreement they made when they took the job. All of them could have refused, some did at some points, but they took the job, and most of them did it.
We all have to deal with shit, if you haven't yet, consider yourself lucky (and spoiled). You keep ignoring almost every point everyone makes, they were not coerced into it, they were not threatened, and it was never implied as you keep saying despite how many times you have been told that is not the case. You are injecting things into this that simply are not there.
A normal person sees this scene and wants to help the characters and change their lives for the better, an asshole wants to see them treated worse, and a spoiled brat tries to get the artist to change their story to suit their desires.