In our hypothetical narrative about a patient and his social worker, the thing to understand, to get the correct perspective, would be that this is organized slavery, not merely an incident of abuse by one bad apple.
Just imagine, if the social worker had frequently been backing Ben up to the door inside her office, or the door inside the office of another staff (let's just call him Bob H) and getting her jollies for a couple years, and if the doors had windows, so anyone who walked by on a busy clinical unit could look in... and if several other staff (let's just say another social worker named Drew, and the psychiatrist Dr. J) had actually confronted her on occasion, to a minimum degree at least (i.e., not quite saying, "Hey! Were you performing fellatio on that patient?" - but perhaps by asking, "Why were you in that room with him when he's not even your patient anymore?" - or perhaps just by giving the pair an accusing look of recognition).
At some point, people would have to be regarded as complicit. It could be said that they certainly would have known something was going on, unless they just didn't want to know. Unless the dominant culture of the plantation held "patients" (slaves) to be just a bit subhuman, so usually wrong and culpable, and "staff" (masters/overseers) to be naturally superior and benevolent, so always right and needing protection. At some point, it would be reasonably seen as organized slavery on the state-run plantation.
The medical perspective would be especially ugly. Sexual abuse is recognized more and more often in psychological literature as a cause of personality and mental disorders. Our hypothetical victim, young black Ben, is supposed to be committed to the Elgin MHC plantation for treatment that could improve his illness, which would of course be the exact opposite of being made worse because a social worker wanted a personal sex toy. The psychiatrist who is in charge of the treatment program, and the medical director who is her ultimate supervisor, and the department of the executive branch of state government which hires and fires people, all would have failed in their duties to prevent something like this from happening.
And in the final analysis, all of us, the taxpayers who fund and benefit from the plantation, should be ashamed. We would have set this up because we don't want to think about or look at insanity. On some level, of course, we would have known that psychiatry is destructive nonsense, not a regular medical specialty that ever cures anyone of anything. But we wouldn't have wanted to know. The plantation gives us valuable benefits by letting us believe we are a kinder, more rational society.
It's a strange thing that Americans want slaves, but they surely do.