The logical leaps they have to make to justify their warped world views are truly worthy of Olympic medals. How would you even trick someone into believing that they were physically abused? Physical abuse is, in most cases, pretty cut and dry. Sure some people might be wrong about the definitions, like proponents of spanking not viewing that as abusive, but that doesn't really change reality.
I suppose in situations where people have been worn down psychologically, getting them to recognise the physical abuse as abuse, and not justify the behaviour of their abuser is actually quite tough. I was that person too, and it's really only in recent years that I've by and large worked past it.
Couple of years back my mother sent me an email out of the blue, talking about how I'm miserable and blah-blah-blah. It came as news to me as I'd been having the best year of my life that far. The levels of projection were laughable. She finally clocked that when I cut contact, I cut contact. She moaned and wailed about how I was cold and abusive like my father, the same person I'd never met because she'd hid his existence from me, and lied about him to my face for 25 years.
Sorry to say, mother dearest; if I'm a monster, I'm a monster of your making. But most people actually find me quite pleasant.