It sounds to me as though your mum was damaged by her own parents and has some inkling of that fact but hasn't really worked through it. So she's torn between blaming them and seeing them as fallible humans that she sympathises with.
She was brought up to believe her upbringing was normal, and has since learned that there may have been things wrong with it, but she's not really putting it all together, so she's veering around all over the place. Your suggestion of joint counselling sounds really helpful, but sadly she isn't ready for that step.
As for others. Some will not see abuse where you do. That's not to suggest it didn't happen. I have no idea what actually happened, but people have different perspectives. People internalise abuse and think it is normal. People turn a blind eye for their own self-preservation. Some people would call something abuse that another would label understandable. For example I've seen where someone was told their parents were abusive for shouting at them, but where a young mum was told that shouting at her own kids was 'perfectly understandable, being a new mum is hard'. It's not all objective, but that doesn't matter, because you don't have to be around someone that you feel abuses you, regardless of someone else's opinion. Especially when that person has said they don't want a relationship with you.
And btw I would certainly class telling you you're not as good as other people's children and haven't done well enough in life as abuse. That's not someone wording things badly because they are stressed and don't know a better way, that's deliberately hurtful.
You have also told her how to fix things and she has refused. It may be that she simply cannot see your point of view, but as she has refused to consider counselling which might have helped you both, the estrangement is really her choice now. So she's hurting herself as well. Sad.
Last letters make new words - Series 3
