There are some people who just cannot apologize. They lack the social emotional skill of context and situation awareness. They are handicapped to some degree, they lack the basics of the literacy of feelings. When they say they can’t they are telling the truth they do not have the wiring, skills or equipment to get the apology done.
Have mercy and pity on this group as they are many. It is as if an entire section of their brain remains unwired. They are truly the unfortunate ones as they will go through life laying waste to those who cross their path.