Why is it that dildos and other forms of sexual humor are okay for film and TV but not videogames? And this coming from the guy behind curb stomping and beating people with their severed limbs?
I'd say it would have to do with the notion that film-making, as an art-form has been proven as legitimate by society as a whole, where as gaming hasn't. Low-grade movies that focus on "immature" humor can exist and have no lasting effect on what people think about the film industry as a whole because film-making has had its reputation forged over the past 100 years or so by the likes of Orsen Wells, Hitchcock, Kubrick etc; When you think of movies as a whole, you don't automatically think of 'American Pie', or 'The Godfather', for example. You think of it as a medium capable of both extreme's and everything in-between.
Gaming hasn't reached that point yet (if ever), and I'm guessing Cliffy is thinking along the lines of "a rising tide lifts all boats" in that as an art-form, we still have to reach those artistic highs before games like 'Saints Row' and in turn, an inherent immaturity isn't seen as the norm.
I agree with the second part completely though. If anything, a critical comment on the immaturity of certain games shouldn't be coming from someone who's responsible for mass market perceptions of gaming as violent and immature by including (as you say) the likes of curb-stomping and chainsaw-guns. It's kind of ludicrous, actually.