Brooklyn 19,
I alawys understood that story (with dovid) as follows:
If the color purple would have been unbecoming of a king she would have rebuked him for that, the thing she was rebuking him for was not his leg showing per se but rather that she felt the way he was dancing was unbecoming of a king.
i may have been wrong although i think my way makes more sense
if you have a proof that she was rebuking him because of the leg per se (and not because showing the leg was unbecoming of a king at that time) please post it