I would suggest they did not decide to be bad parents, but simply didn't recognize the need to do better. It's not an excuse just a truth. Children learn from their parents one way or another. The person you are when you entered this realm determines the way you will interpret your lessons; to mimic or be the exact opposite.
I too chose to be the exact opposite in many ways. My forgiving my parents for simply being who they are (and I in no way suggest I have experienced what you have; in no way would I dare minimize your anguish and hurt and experience of abuse) allowed me to find a happy medium in many areas of my life.
Holding on to the anger slows us down and keeps us from finding solutions for ourselves.
Please believe me when I say, I wish forgiveness because it helps YOU heal. It is your own, personal, and true blessing; the best gift you could ever give yourself.
Forgiving them empowers/liberates you to separate your intentions from theirs. It lightens the burden of their control and makes you lighter and stronger on your way out of the abuse.
