What the what?
The last one is what gets me the most. People are upset because that is behavior unbecoming of a role model to little girls. Lets look at the definition of role model, shall we?
a person regarded by others, esp younger people, as a good example to follow
Collins English Dictionary – Complete and Unabridged © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003
Why, as a parent, would you (general you) perpetuate the idea to your child that an entertainer is a good and/or appropriate role model? Sure, I can see kids seeing her on TV and listening to her music and thinking "I want to be like her." But you know what? It's our job as parents to make sure they understand that they don't know her. What they see is a character, no more 'real' than Scooby Doo. It is OK to derive entertainment from her, and enjoy what she has to offer, but aspiring to be like her when you don't know her, or what she's about, isn't a good idea.
Miley Cyrus is an entertainer, and she has her own agenda - that agenda does not include making sure your kids have appropriate role models. That is YOUR job. YOURS. So now you know a little bit more about what she's about... move on. Help your kids find a solid role model they can relate to - preferably someone they know or at least have a chance to get to know.
If I'm being honest, my first thought when I saw that clip was not "OMG. What a terrible role model!" It was "Oh lord. This needs to stop. Another Disney girl, on the downward spiral... next stop, rehab." I was actually worried about her, and wondering if she was going to be the next Lindsay Lohan, or take the same trip to Crazyville as Britney Spears a few years ago. It's just sad. I actually really hope this was a calculated ploy to take her career in a new direction, and not the beginning of another very public, very bad, crash and burn.