Even if I were to stipulate to that... so freakin' what? Smoking is destructive. Fatty food is destructive. Each person decides whether the risk to his health of smoking or eating one of these is worth the enjoyment he derives from it. It's this thing called freedom... perhaps you've heard of it.
Far-reaching destructive tentacles, that porn stuff.
You want to unravel society?
The level of porn that is pervasive today is a good start.
Don't care about society?
Enjoy your porn.