Not everything legal is healthy for society. Abortion is legal. Homosexuality is legal. The line has to be drawn somewhere. It may not end in making things illegal but there has to be standards set in society.
My point is that the line HAS been drawn. It's legal. That's the line.
You seem to simply that there are no standards--there ARE standards, there ARE lines. Child porn is illegal. Just about anything else goes. That is a line, that is a standard.
Again, sorry that you don't like it. But no one puts a gun to your head and makes you watch porn. Unless, of course, you're in an Iraqi prison camp...