Creativity is not the same thing as creating art. Mashups cannot be considered art because the creator did not add any new material. It may be creative or interesting or intriguing but it is not art. Remixes, though they may add some new material cannot be considered art either because they fit into a frame created by someone else.
I would say that these are indeed assaults on originality not because they distort the work of someone else but rather because they blunt the drive to create new material. Simply finding interesting preexisting works and meshing them together does not generate original material. Can the process be creative? Yes it can. Is it original? No, not really.
By the way I think that they can be funny. This one is my favorite.
As for education I am a bit troubled that such a debate exists. Considering how the United States seems to be slowly but surely falling behind the rest of the world in math and science (as well as writing and reading comprehension) I would not even consider teaching such material to children much less debate on what form it should take.
Can we please focus on the time-tested foundation of the three Rs?