Some not so random thoughts reading different comments:
What might be considered provocative in one culture is considered a normal every day activity in another.
Some seem (of course, I might be completely misunderstanding them) to be making the leap that forgetting the “shivisi hashem” principle is somehow equated with a lack of tznius.
Most exercise routines involve the movement of certain body parts one should refrain from doing publicly. In fact, bending down to touch your toes or doing jumping jacks (which my daughter does in her typical BY school with the “exercise morah” 2x a week) involves such movements as does ballet. Why the particular brouhaha over Zumba?