While parents are obviously older and more experienced than their children, it is frequently less obvious that their particular experience or knowledge has given them exclusive access to the truth or provided them with sufficient wisdom to judge always what is right and wrong. "Experience is a good teacher," but it does not always teach what is right; knowledge is better than ignorance, but a knowledgeable person is not always wise.
It has impressed me to see how many parents in deep trouble in their relationships with their children are persons with very strong and very rigid concepts of what is right and wrong. It follows that the more certain parents are that their own values and beliefs are right, the more they tend to impose them on their children (and usually on others, too). It also follows that such parents are apt to be unaccepting of behaviors that appear to deviate from their own values and beliefs.