What's wrong with writing to your audience? Isn't that kind of the point?
There's nothing wrong with writing to your audience. Although since Whedon is a nerd he more likely writes what he likes and others associate with it. It just turned out to be a niche that works for him. He has a small bag of tricks and this way he can use it over and over again. The point is that Joss Whedon touched Barnes and Skeletors peepee's when they were children. So now they're terrified of clowns and popular geek TV shows.