...as simple as it is to get one's hands on a computer and internet access, parents should similarly be equipped with the tools and knowledge to be able to better manage their children's online business. Slashparents, I'm sure, don't have an issue with such things (think worst-case heavy-handed approach with keyloggers, parental filtering, logging, webcam capturing
There's the concern, too, that if your 7th-grade kid is defaming someone on Facebook, then you've already failed this 13-year old with poor parenting choices during his formative years, and the impact that parent-driven punitive measures would have at that point in his life are minimal, compared to if the courts got involved and punished the kid for you.
The truth of a proposition has nothing to do with its credibility. And vice versa.