Sometimes, good or basically good people are not necessarily good parents, but not bad. My father had his issues, never intentionally "mean" but sometimes quick to yell. Many of his issues were the result of alcohol which I learned was a result of a rough childhood himself. I never met him, but his father, my grandfather was I was told a mean, mean man. How much did that impact my dad? A lot I am sure.
I came to terms with any issues I may have had with him by realizing he did try to be good. But as a parent of three, i know I would like a do over of certain events with my children. But you don't get it. I am not suggesting you feel one way or the other but maybe they did what they thought was right, but we're wrong.