However, I don't see it as theft, any more than I see a production of a Shakespeare play as theft. Stealing is when you're dishonest about the source of your raw material and represent it as your own creation. An interesting juxtaposition of known material is a commentary in itself, regardless of whether you like it; and the guy's career is as a producer, not as a musician or composer. For that matter, both Mozart and Bach were regarded by some as mere hacks, appropriating or accepting tunes from others and applying mere technique to arrive at elaborate (but not fundamentally complex) arrangements.
I'm unsure why you seem so personally offended by this, to the point of finding it indecent and dishonorable. I've been blatantly ripped off by a (book) publisher in the past, and it made me mad, but not to the extent of rejecting an entire branch of creative technique. Can you explain, without the invective?