The article is phrased in the language of disappointment, built to emphasise that someone is being let down or not being treated right – hence the quotation about how much he was looking forward to it, the point about the text and so forth. That’s infotainment for ya!
Another way of looking at it would be that what is being commemorated is not ‘Nirvana’ as a full historical entity – in which case why draw the line at inviting Chad? Why not invite Aaron, Dave Mk.1, Dan, Dale, Jason, Pat…? The Rock and Roll Hall of Fame sells peak fame, not the years of puttering along, so realistically the induction is a celebration of two things; the Smells Like Teen Spirit single and the Nevermind album – nuance and the kind of ephemera that keeps fans occupied is far less relevant than than the one song most everyone in the world remembers plus that ‘album with the baby on the front’ that tens of millions of potential Hall of Fame customers purchased. In a way, what’s being celebrated is two spikes in attention, not even the full two and a half years of fame (let alone the full winter 1986-spring 1994 band), just the explosion around Nevermind and Teen Spirit in late 1991-early 1992, then Cobain’s elevation to sainthood in 1994.
An argument could be made about Chad’s contribution but what metric to use? Grohl serves 41 months compared to Chad’s 24, Grohl plays 207 shows compared to Chad’s 140, Grohl records 59 songs over 7 recording sessions while Chad records 35 over 6 sessions – again, if the other drummers are excluded because they’re not around long or they don’t play much then it becomes tenuous arguing Chad ‘did enough’ he should be there. An argument based on quantity doesn’t really cut it.
A different argument would be that Chad lay down the drum patterns in studio subsequently followed by Grohl on around half of Nevermind thus making him a contributor – unfortunately that again opens up the door to inviting others given Polly was first attempted either with Aaron or Dave Mk.1. It’d also make it hard to exclude the others given a lot of the work on Bleach was first created by Aaron or Dave though subsequently recorded formally by Chad. Too many blurred lines to exclude anyone unless everyone is excluded apart from the guy who has become most comfy alongside the LA/NYC rock tradition and business.
That’s where the shame is really, having true representatives of the late Eighties’ North-West underground on stage would be a joy – guys who really did slog it out for no thanks and no cash in the times when Seattle was barely mentioned in a musical context so the people making music there had to love it very much to want to make something happen. It’d be a nice contrast seeing Aaron’s weathered rock look, Dave’s everyman expression, Chad’s ‘pixie of eternal youth’ walking out past the applauding suits. That would have been a real statement saying that Nirvana really had broken the line between underground and mainstream – instead the ceremony will be a reminder that the barricades were rolled back across the path soon enough with those deemed less able to commoditised ignored.