Mike - Sure, there's a long history of punk flyer appropriation. I wonder, though, what sort of recourse they would have had if there was a site like GP to have all the knowledgeable artists call out the ripper-offers back in the day. I bet most folks, like me, had not much of an idea who the original artist of this was. (Of course, the slap-together job of text and hearts makes it more obvious) Would the public know that it wasn't original? PRobably not necessarily. So an artist is much more susceptible to this type of criticism when they have posted their work to be examined by a group of their peers.
Plus, look at the dude's attitude/argument/defense. He's straight "Paul Gardner"-ing it. Deserves what he's getting.