I don't care what they put for number one, nor do I care about presence of Zepplin nor Van Halen. The 70s list was the only one that displayed variety, most likely due to indie rock not existing in that decade.
Anyway, what's wrong with those two bands being on the there? Just because you don't like them? It's a fucking list, ya know? Of course there's gonna be bands you don't like. Since the ranking of the albums is largely irrelevant, the only quibble I have with Pfork's 70s list is their basically saying Miles Davis was the only jazz musician to do anything of note in that decade.