For truth, abuse/neglect is passed like a virus from one to the next, and has been about too long for any of us to remember.
I've known both personally, and on both ends they do fester in a person til it's let out on another unsuspecting victim.
Though hard, those abused have to pick up alot of slack and ultimately swallow down a most bitter pill, and let it go forever, because though they didn't ask for it, they have to deal with it in this manner or else they will without doubt pass it on to another child. And that is guaranteed every time. They do it as revenge or do it because they've known no other way.