My Ancestors by Lou Rawls (Safe for Everyone Everywhere)
It's not about what someone does for a living, say. but where they are in their head; what are their intentions for doing what they're doing. In science, for example, I would consider someone who falsifies results for money and or fame a mental slave. I would consider a plagiarist a mental slave. A scientist who is ethical in their studies and whose only base goal is the furthering of human knowledge to positively benefit humanity...that is exactly NOT a mental slave.
In a social context, a mental slave might be someone who is confined to a way of thinking that is detrimental to society and the sub-societies they touch. Racists, homophobes, sexists, and their enablers are mental slaves. A judge who gives a 6 month sentence to a college student caught in the act of raping a woman is a mental slave. A judge and jury who find a man innocent of shooting a youth armed with only an iced tea...they're mental slaves. The Germans who followed Hitler were mental slaves.
The comparison to Stockholm Syndrome comes from the idea that, while every individual is responsible for their own thoughts and actions, there is a certain amount of responsibility to be placed on the past and the environment it creates. The "abuser" in the case of mental slavery is almost always a larger ingrained ignorance that's culturally instilled. The "victims" who stick with their "abuser" are people who have been mentally programmed (in a sense) to stay in the comfort of a mentality that benefits the "abuser ". For example, the (ridiculously light) sentencing of the boy who was CAUGHT raping the woman at Standford benefits an archaic, negative social construct: the "powerful white man's club", where the privileged can find mechanisms to justify their evil behaviours (and I don't use "evil" in a religious sense.). The victim is the woman, no argument can be made otherwise. In the context of Mental Slavery, though, the "victim" is the judge (and probably the boy). I really want to highlight the parentheses there: "victim". Of Mental Slavery. They're "victimized" by the culture that goes back to slave owners and overseers using slave women as sex slaves. Now there's no slaves, so the culture has bled over into society as a whole..
(I recognize the privileged raped their own race(s) and other races as well, African slavery in America is just a very poignant example, and it DID go on for an awful long time, so as to become very ingrained in the mentality of slave owners, overseers and their offspring)
Freedom from Mental Slavery requires a conscious effort on the part of every individual to not only understand the abusive societal patterns we fall into, but also actively work against them and instill in the subsequent generations an alternative (hopefully positive) to the "abusive" social constructs we allow to victimize us.