Whenever I hear about stuff like this, I wonder: Is there anything the failure modes of the human brain allow us to deduce about the software architecture? Maybe memories are stored in some partitioned database, and one of the partitions is always stuff relating to "my identity", and somehow this partition can get unlinked and temporarily re-linked to a blank one, which is discarded after a few hours. Hmm, maybe this…
However, making evolutionary arguments for psychological traits is tricky business and while I'm not a professional evolutionary psychologist myself, I think the explanation you gave violates a fundamental principle of evolutionary arguments.
Imagine gene A confers a fitness advantage because it allows a person to better cope with a selection pressure X, and gene B confers an additional fitness advantage against X, but only if gene A is present, and does nothing otherwise. In this (common) case, gene B will not be selected for unless gene A is already universal in the population. Following the same rules, imagine we then get gene C which is dependent on B, then a variant of gene A called A* which is dependent on B and C, and so on. Eventually, if even one gene is removed (either by sexual reproduction with someone who doesn't have it or by mutation), the whole tower falls down and the entire piece of complex biological machinery is broken.
Basically, there's no way for selection pressure X on a significant chunk but not all of the population to produce a piece of complex machinery (read: involving 2+ interdependent genes) in the first place, and it would be broken beyond all repair in all offspring who didn't have both parents with the full genetic instructions. So the idea that "many humans were abused, enslaved, etc." only works if the selection pressure was on everyone and the adaptation is universal in the human population, unless it's attributed to a single mutation.
The rarity of this condition isn't consistent with it being a feature. Seems like a bug to me.
Hope this was helpful!