Some people have become hardwired to never being at fault, never accepting blame, never taking responsibility for how they inflict themselves on others, and not even having much awareness for how injurious they are. It's always someone else to blame, someone else who has the "deep problems" interacting with people. You won't get a genuine apology out of them, i.e. "I'm sorry I did X." They will say, "I'm sorry that YOU FEEL X". Which is a lie, they aren't the slightest bit sorry even for that. Trying to argue with such a person is frustrating, until you finally realize they are pathological and you're completely wasting your time trying to get any accommodation out of them.
One can ask oneself, why are some people like this? In some cases I think it is because they are old, have gotten this far in life abusing people this way, and have no incentive whatsoever to change how they treat people. They will die this way. They may even have a few decades of their obnoxiousness left in them, to inflict on others before they go down. It's interesting to contemplate the fate of the species when a certain contingent of human beings are like this.
Why do they become this way in the 1st place? I'm not sure, but I don't believe anyone is born this way. I think it has to do with some kind of emotional injury some time during their life. To cover the wound, an impenetrable shield is developed which brokers no compromise.