Do as I say

Has anybody else noticed that if a parent is unkind to his/her children, people will say sympathetically "They can't help it, that's the way they were raised." Whereas, if a person was mistreated terribly by their parents for many years, people say it shouldn't have any effect on them (outside of how they treat their own children). Parents hold themselves blameless if their children turn out badly, but take credit if their children turn out well. Is it really fair or logical that we expect children to behave better than adults?