Have you asked your DD what's going on? What does she say?
It will likely be hard to start (or maintain) that conversation without being accusatory or judgmental (at least it would for me . . . ) but the key is really to avoid those things. Try to stick with a CURIOUS mindset aimed at UNDERSTANDING her. You want to convey (and be) puzzled and curious and genuinely concerned about her feelings and values, not so you can judge or "correct" them, but so you can understand them from her point of view.
From there you can think about if or how to address the situation. In a separate conversation another time. The first conversation is listening and understanding only. Not advising, critiquing, or correcting.
If you do this, please post back. I'm actually curious what your DD is thinking.

Is she shy? Intimidated by adults? Showing off for her friends? Amused by the thrill of being "bad"? Enjoying the negative attention? Completely and utterly clueless about it all? Or something else entirely? Kids are complicated and rudeness is not always rudeness. (Although sometimes it is . . . . )
