TTT - // AH: "You have to possess the intelligence to understand respect as a concept," - indeed Andy, sadly their are morons among us who find this sort of thing amusing. //
I honestly believe it's not even as sophisticated as being rooted in a sense of humour, which again requires a modicum of intelligence.
I think these people, brain-dead as they are, register on some simple level, that their lives, and their input into society around them is meaningless and worthless, and it is a desire to make a mark, however pointless or temporary or distressing, that leads them to behaviour like this.
They can tell their friends - and themselves - "I did that …" and feel as though they have done something to identify themselves as other than the pointless waste of fresh air that they actually are.