HOW IS THIS NOT SLUTTY!?

Okay so my friend and I always go to u18 events. She moved schools to some sport high school and I'm still at a catholic high school.She hangs out with the I guess slutty crowd and yeah. At this rave she was dj-ing and so she was already there when i got there. She was wearing a cheetah print bra, shorts that just covered her *** and high heeled black boots! Yes she did use to be chubby and now she lost all this weight but this doesnt give her the excuse to dress like a skank! I think it'de be different if it was a girl that was flat chested and didn't have a good bum but this girl has mive and a good bum and no stomach! Okay so through the night after she did her time Dj-ing another Dj went on and she went to take pictures with a line up of 15 and 16 yr old guys! To add to that she was grinding and making out with a load of different guys! She thinks it wasnt slutty at all how do I tell her ?