Nothing to be ashamed of mg, the old saying of "I blame the parents" is usually a load of old bollox. Yes parents are responsible from teaching their children right from wrong, and I'm sure you're children do know right from wrong.
However, try as hard as you like, but you can't always make sure they put their knowledge into practice. Uninstalling MSN was the only thing you could have done in this case, the most you can do is remove all means that enable them to do it again.
What he did was nothing none of us haven't done or said before at some stage during our childhood or indeed our adult life. I'm sure it's all on the surface and when confronted with the situation in real life, he wouldn't behave any differently towards the people in question (I'm speaking slightly in code, but I'm sure you know what I mean)