If porn really was that prevalent, then I'd spend most of my working life disinfecting keyboards and fitting monitors with wiper blades. In reality I never come across it (no pun intended) either on my own system or those of clients. And some of those can be pretty ropey.
No, what this is all about is information control. Scare the herd, so they don't go wandering around the net and find out the real story. Keep the Great Unwashed under the thumb, don't let them think, to question, to spot the holes in the doctrine you could drive an OIL TANKER through.
You can see how it's working. I got a lift back from the hall with the MS I'm allegedly studying with & his wife. I said something along the lines of "the net isn't all bad, I downloaded the assembly program off it. And got the new DVD too...". You could see the colour visibly drain from his face. Poor chap. He's a good man, but he laps every word of this up like a starving dog in a gravy factory.