It doesn't take into account different personality types. Aggressive people like getting into confrontations and winning, while the more bookish might prefer to avoid conflict, and would feel bad when pressed into one.

When we know something is wrong,

wrong to a middle upper class researcher may not be the same wrong that a combat soldier or an "urban youth" makes moral decisions based upon

This demonstrates the importance of the psychological dimension that I talk about in much of my original work and other posts, which is of how our level of consciousness and the ability to evolve our consciousness reflects in changes within our physical brain itself.

I won't argue against this point

I wonder if those who continue to do immoral actions, harm others, mistreat others, create a feedback loop through the changes in their brain where they continually devalue assessments about harming others which keeps them harming others

as long as people are get a positive overall reward for a behavior, they will continue to do that behavior, so yes, I'd say the person in this case has trained his brain (even unconsciously) to reduce the negative effects (guilt, shame, etc) in order to maximize the pleasure of the act.