Young men and women come of age when they look at their parents and see them not only as their parents but as people. They gain a lot of compassion, and it's easier to accept their flaws.
Absent parents aren't abusive per se. They're neglectful. They love in a very imperfect way. There are parents like that, and they do love their daughters and sons, but they're not parents in the way that we might think of it.