Actually, I think there's some gray area in the law. Men touch women (and vice versa) in sexually charged ways all the time. Sometimes it's explicitly agreed, but often there's some wishful thinking going on.
A quiet withdrawal from the touch, a hand moving the unwanted hand off, a demurral, an outraged demurral, or a slap, and the incident is over? Isn't that how it often goes? Does the law have to make a felony of every such unwanted incident?
What Clinton did to Willey went a long ways into the gray area, all the way across it into the red I think, but there really is a continuum and it's not all red.