They did steal a lot (certainly not everything) but everything they did steal was far better than the original, and ultimately, Willie Dixon became a very rich man out of the deal. At the time of them lifting a lot of blues stuff EVERYONE else was too, though i never understood why LZ didn't give credit. Even so it doesn't remotely diminish their talent, or their place in history as one of best, most influential, and most important rock bands. They are hardly second rate hacks.