Paris Hilton was also another style icon at the time. The Von Dutch phenomenon is largely contributed to her (at least for women...), along with the track suits.
Jennifer Lopez was another one
But it's the same reason why once Lady Gaga got popular everyone started dressing "weird"--just trying to keep up with what's selling/cool.
__________________
"Remember, don't let others dictate your music taste. If you like whatever you're listening to, keep listening to it."