Just a couple of notes:
0.) Dead humans are generally a terrible
food-source for live humans.
1.) Even if it were a great source, the system as described is doomed because of inefficiencies in metabolism and reclamation.
2.) Humans are terrible sources of electrical power; given how hard it would be to go from 0.) to 1.), energy inputs likely to swamp any gains would be needed.
2.a.) It would have been a lot better if the humans were needed for their brains' processing power; this would make the whole thing an even better metaphor, as the root of the problem always boils down to 'us' (well, 'us and physics', pretty often).
3.) In the U.S., "The Matrix" is a trope on the Right, I think for the false reality in which people are made to believe so that they don't recognise their domination by Mud People, the Space Masons, and Mystery Babylon.
Of course, Morpheus is an oppressed person the machines have tried to keep ignorant, so why shouldn't he accept the first reasonable-sounding explanation he ever heard? (Yet another reason http://www.spectacle.org/0802/hogan.html