I think everybody has the right to choose who they want to have in their life, and who they don't. It shouldn't even need justifying and most certainly not when everybody is in agreement that the person is a horrible person!
I've cut my father out of my life for a whole catalogue of reasons. My mother respects this. Well, really she just doesn't oppose anyone or anything because she's so frightened (she's been very abused). My brother's haven't yet worked it out and it hasn't come up for me to say just yet (speak when spoken to, I am a coward). I know they won't respect my decision (I've always been forced to have contact with him, forced to take presents from him, forced to 'be nice' etc.) As a child my choices, my freedom to make decisions, my right to have feelings, and ultimately to just be me - it was all taken away from me. I don't feel I have yet fully reclaimed my right to act on my own behalf and make decisions based on what I believe is for my best interests. The decision to cut contact was made because of what I found out he had done to my mum. Not the misery he put ME through, but the misery he puts her through. But if there's anything that I will fight for, it's my helpless mother.
I'm sorry your aunt is putting you through the judgements, invalidation, and attempts to control. My family are similar. None of them spend much time with him if they can help it as they all agree he isn't a nice person too -- but nobody but me has made the decision to not see him again. I think that, unfortunately, some people refuse to let go of the illusion of 'family values' when they are in a dysfunctional 'family' that never upheld those values or fulfilled any of the functions and purposes that a family is meant for in the first place. Which is what makes the word 'family' an illusion to me. Sounds like your aunt is projecting her issues onto you, because she can't deal with the reality.
My family buy into the pretense and the false sense of security that this illusion gives them. I think it allows them to think that because they can act as if there is a family, then they are 'like everyone else who has a family too'. Because to think of yourself as someone without a parent or family or family member in your life can be lonely and painful. Some can't take it. Whilst I have an abundence of issues, at least I can see them for what they are. But they can't see their issues, they live in denial and it is crazy to me. They think that being blood related is what it means to be 'family', and that as this tie can never be cut neither should any familial relationship. But I disagree with that. I believe that relationships are supposed to be positive, not abusive. I take the stance that this is my life, it belongs to me, and to an extent I can pick and choose what and who I have in my life based on any reason I feel fit. For me that's having a basic freedom to be me and to have and use the basic human right to make my own decisions.
Sorry I think I might be ranting. How does it make me feel that I don't speak to or see my father? It's just a relief to get him out of my life as much as I can. He's brought nothing positive to my life whatsoever. He only ever inflicts misery on others. However, because I have made a decision, it means that behaviourally 'speaking' - I have "spoken". It means there will be a day when that will be realised and I will be confronted. Then I will have to stand by my decision by speaking words too. That frightens me. But I know that it is important for me to deal with that at some point. If I don't stand up for something, then I stand for nothing. Being me must mean something? At least to me, even if that means nothing to them.