It's a well known fact that it is quite difficult for some parents to setup and use parental controls, I believe it was just to fully explain it to people that might not know much about how parental controls work.
And how many parents are watching a WWDC presentation?
its a developer presentation not a consumer one. Save it for the iPad refresh when parents are watching rather than wasting dev time on it.
Even then it could have been 15% of the time with literally the same info.