One thing that has always bothered me (and bothers me with greater intensity as this narrative becomes more commonplace) is the implications of the moral standard of, "They are poor off or went through bad childhoods, so it's excusable when they steal, break the law, or kill." This ignores the people who don't. The people who go through a shitty childhood, are abused, are treated like shit, and don't abuse others, don't treat each other like shit. By incentivizing and excusing bad behavior with the notion that "they deserve it after what they went through", you communicate to those who played by the rules after suffering that they are suckers. That they made a mistake, and should have been acting out, breaking the law, etc. It's fucking horrifying to me, as someone who grew up poor and neglected.
The best way I can think of to crystallize this feeling I have is this: Every time "righteous" liberals overlook the crimes and failings of those who act out, they condemn and wrong those who went through just as much suffering, but don't do anything wrong.
On a larger scale, I think this is largely the rot ripping through our society even in purely white communities. It is the idea that having an old-fashioned sense of morality and playing by the old social contract makes you a rube. Not ripping off others makes you a sucker. This downward spiral is probably how most countries end up as "shitholes".