Led Zeppelin are posers?

A friend of mine turned me onto this. Led Zeppelin I, a definitive Zeppelin album is, in fact, a plagarized piece of garbage. Only one of the nine tracks is actually an original song. The rest were uncredited covers of older blues and folk songs that are only recently being credited to the rightful artists. All of the evidence is spelled out here: Cold Cases of Rock Although the lack of audio tracks on the site is disappointing, I have heard almost all of the original songs and cannot look at Led Zeppelin the same way.