Sex vs Violence

Why is violence more acceptable than sex on TV and in the movies?  A movie like Hostel where people get eyes cut out of sockets and other torturous acts get "R" ratings. Yet the minute a movie just shows the nether regions of a female or a male they want to slap an NC-17 rating on it. Cutting a foot off with a hacksaw= "R" rating....oral sex= NC 17?? Our society is more afraid of sex than it is of violence. Remember the hailstorm Janet Jackson's boob set off a few years ago? Even the President of The US chimed in on that one....he said it was so offensive. One boob did all of that!! Im just thinking out loud....dont mind me!