Maybe they're doing it because dressing like that makes them comfortable with how they look, showing off certain parts of their bodies that they're impressed with and like. Believe it or not, most of the time girls don't dress for the sole purpose of you liking it, the world doesn't revolve around you dear. I wear crop shirts and hoodies because my upper body is something I'm impressed with and makes me feel comfortable. I don't wear shit to impress guys.