Well the people who write dictionaries for one. If you look up the definition of dance one of the results is "the art of dancing" and under origin and history it lists:
Originally Posted by Kashmir
c.1300, from O.Fr. dancier, perhaps from Frankish. A word of uncertain origin but which, through French influence in arts and society, has become the primary word for this activity from Spain to Russia. Replaced O.E. sealtian. Related: Dancer (mid-15c.)."
I have never actually heard of any dance NOT being considered an art including "just raqs, and raqs sharqi, and all the others", they're all art. Any art that has strong ties to a culture does require that those ties be treated with respect be it dance or painting etc.
So while I agree with you that saying "we like your dance so we'll define it as 'art' then it belongs to us" is wrong that isn't actually what sultan said. She said that "no one group can claim it to the exclusion of all others" and with the possible exception of arts with religious significance I have to agree.