I think the real reason is that it's not really porn they're worried about...it's the Internet.
Undercover, you are so right. Paragraph 9 is ostensibly about the dangers of pornography, but its real purpose is to scare the rank and file away from the Internet.
Imagine an Internet where porn comes looking for you. Just logging on puts you at risk! With every opened email comes the risk of a porn explosion! And to make matters worse (if that were possible), it takes only a "glimpse", just a "brief brush" with this pornography to cause irreparable damage to your mind.... And in case you don't believe us, here's a "Christian brother" and former porn-addict to tell you about his 25 years of hell battling against the images that are now permanently burned into his brain.
OBVIOUSLY, using the Internet is just not worth the risk....