Why do teen girls think they're sexy?

Lately, so many teen girls in my hs have been looking trashy and slutty, and the funny thing is they think they're sexy. Why do they want to look like a wh0re? Yeah, they'll get attention from guys, but not good guys. Just the sloppy man wh0res. I just wanna know why they want to look this way, and why they want all this attention?! Its rediculous...