Rooster Ties is being ironic. There has been massive controversy for decades on the Led Zeppelin writing credits, and I have generally found them "guilty as charged". And they most definitely are guilty here (I loved Spirit, play them a lot more than I play Led Zeppelin), on "Whole Lotta Love", on "Black Mountain Side", on "Babe, I'm Gonna Leave You", on "How Many More Times" etc. They've even discreetly admitted so at times,with "amended" composition credits. They are hardly alone in that regard, but were incredibly blatant, and there was a lot of songwrting royalty money involved, so it has drawn a lot of attention.