Some video games are interactive porn, yet a 10 year old can buy it.
Go on. Show me a video game that's interactive porn widely available in the US. Bonus points if it's rated E so that a 10 year old can actually buy it.
He can't, because there are none, unless you reeeaaallly stretch the definition of "porn." Even the most "adult" mainstream games out their (GTA, etc) are at most the equivalent of an R-rated movie in terms of adult content.