Thanks for sharing this. In my life, I have been both abused & the abuser. And, like you, I am plagued by guilt regarding my past deeds. It is part of the reason I have become mostly a recluse. I consider it to be my gift to the world, or at least that tiny portion of it I inhabit. No good has ever accrued from me having anything to do with anyone. I have often wished that someone, presumably a mental health professional, could tell me that I have always had some identifiable mental illness & that's why I did the things I did... because otherwise... it means I was simply a bad seed.
I don't recall having read the policy statement that was apparently quoted to you. Perhaps I did. But I would presume that the intent here is primarily to warn off anyone who thinks they can come here & be abusive. Human beings are complex. Yes, I do believe there are some individuals where-in the bad is so overarching that it simply swamps any shred of goodness that exists. But most of us are complicated mixtures of "the good, the bad, & the ugly"... to borrow a phrase. The Buddhist nun Pema Chödrön has written that bodhisattva's are to be found among thieves and murderers.
I believe that the important thing here is whether or not a person can be a caring supportive member here on PC... not whether or not they've ever done anything that could be considered by someone to be abusive. By that standard, I suspect the membership here on PC would be pretty small.

I wish you well...