My quick opinion on the matter:
Either you feel your son's mature enough for an iPod Touch, or you don't.
If you have to lock down everything and turn everything off and yet it's still not 'clean' enough - you clearly don't think your son's mature enough for such a product.
Why not simply buy a Nano and a kid-oriented educational console for the TV, or something?
If he wants an iPod Touch after we had asked him to get good grades at school then so be it.
It's not really much to ask for comments to be moderated. Forget it's my son that saw it, heck I would rather not have to read some of the ones I saw. I'm all for tech progression but heck lets be responsible and accountable for things.
If it was up to me at the least I would have an alert moderator button. Not really that much for a multi billion $ co. to implement. It's all teething problems I accept, there are many things people want to change in the app store on the iPhone or Mac. If no one says anything then where does that get you.