You see underage girls in similar outfits/poses in Hollywood films/magazines/commercials. This is being targeted because it's a web-based operation not protected by a billion dollar industry. Period. Sure, it's distasteful to some... I find many Hollywood movies/magazines/commercials distasteful. But should it be illegal?
I remember a company called Playtoy Entertainment that did this same thing... but with girls aged 10 and under. There is clearly a distinction between taking these types of pictures of post-prepubescent girls versus taking them of prepubescent girls. But where is the line drawn and how do you write a law around it?
Interesting article:
http://www.redherring.com/Home/19972