I think that the video has been taken out of context. If you watch the music video for Beyonce's Single Ladies, you will notice that the routine that the girls do takes parts from the original video, and have been made into an original routine. I think that the girls are quite talented and we should remember that the dance was performed at a dance competition, and not intended for millions of people to see on the internet.
I'm sure the girls realized that the outfits did not cover their arms, bellies, or upper legs, but their hind ends are not exposed at all as the bottoms are shortsm and neither are their chests. The tops are not triangle bikini tops, they are wide bandeau type tops. The outfits are embellished, yes, but the idea that they are meant to make the girls look "sexy" is an adult idea, and an inappropriate one at that. The style of dance is similar to the style of dance that my high school's competitive dance team used when I was in high school. These girls are just getting a leg up on the competition for when they're older. I'm sure they are proficient in other areas of dance as well if they can do the dance they did in the video in question.
Dance styles change over time, and often times older individuals do not find these new styles to be appropriate, but ask yourself; did your parents think your styles of dancing when you were young, were always appropriate? What about your style of clothing, or choice of hairstyle? Did you listen to music that might not have been age appropriate when you were young? Most kids WANT to grow up really quickly, and they absolutely don't want to be treated like babies after a certain point.
The fact that these young girls are doing a "sexual dance" is an adult idea. I highly doubt that the girls associate their dance moves with sex, as I feel that it is very safe to assume that none of them have ever had that experience, or even kissed a boy for that matter. I think that people and the media have blown this way out of proportion. The girls did the dance in a competition, and to win you have to be good. The dance is a contemporary one, not some strange choreographer's attempt to sexualize young girls for the world to watch.
People always want somewhat questionable things like this to become some sort of scandal, and it's quite absurd really. So what if the girls can dance as well as older dancers? They have talent. It may not be the type of talent that some believe is age appropriate, or want their own children to have, but I bet they placed high in that dance competition. The upbringing of a child is the responsibility of the parent, other people should have little to no influence on this unless there is abuse or another serious issue. The girls in the video were having fun, not trying to attract members of the opposite sex.