Kung fu movies are... not big with the kids these days. So a parody of kung-fu movies also appeals more to adult sensibilities. Though it doesn't necessarily exclude kids, being goofy comedy after all. Comedy can be more meant for an adult audience or more meant for a saturday morning cartoon audience. It doesn't have to have world war II or zombies in it to be "adult."
That said, rag doll kung fu is obviously meant for fairly immature adults. :)








