They want to persuade themselves and others that they were right in treating you the way they did.
Good question.. I don't know my guess would be it is some sort of defense mechanism.. Also, IMO most people think that we deserve what they do to us - and they don't really want to do it but we were just asking for it..
Manipulation...pure and simple
Because, as you will come to understand....there are some people in the world who think it's all about THEM.
as it should be. We are responsible for ourselves.. unless you have children