That's overblowing it a little bit. Has anyone tried doing the same thing with third party DVD playback software? I haven't but I think chances are good that it'll work.

This sort of thing is just par for the course and I see no reason to be upset over it (not saying you are, just generally). You've got a for-profit company with close partnerships and deals with various media companies plus their own iTunes store. Of course this is going to happen. But is it a big deal? It's sure a pain in the ass if you really need a screenshot of the DVD you're watching but if you really need it you'll find a way around it.