I don't defend punishing someone for something that you are also guilty of, but try to keep secret. I also don't defend lecturing about something that you don't really believe in.
What I defend is, in some situations, telling someone to do something that you don't. Without this type of hypocrisy, the world collapses.
Ideals are, by definition, hard to achieve. We progress not by making our goals so easy that no effort is required, but by setting goals that are obtainable only after a long series of trials and errors.
The fact is that even the best of people have trouble living up to ideals. This fact is not justification for discarding the ideals, even when the people who fail at them tell us to strive for them.
In fact, sometimes it is the very people who have failed who are the people we should listen to most. An addicted smoker whose lungs are collapsing can make a powerful argument not to begin smoking, or to quit while you can, even when he isn't able to do so.
The Lowest Common Denominator
We use every opportunity to not fulfill our ideals, and that includes finding any person who doesn't fulfill them as justification for us not to. We find one authority figure who has failed, and say "well, if it's good enough for him ..."
In this way we have perfected the art of sinking to the lowest common denominator of behavior. You'll notice that the argument never seems to work the other way. We don't point to an authority figure who lives up to the ideal and say "well, if he can do it ..." Not when it conflicts with something we want to do, anyway.
I believe that we need to stop using hypocrisy as an excuse for our own low moral standards and behavior. We should listen to people when they tell us something important, even if the person telling us is less than perfect.
We should stop being afraid of expressing ideals. If we wait until we are perfect before we speak, we will not speak at all. Don't let others use our own failures as an excuse. Two wrongs don't make it right.
Ideals do not suffer in the hands of man; man can only fail to live up to them. Man suffers when he runs from ideals, instead of to them.