Winston, there's a legend at the bottom of the article that specifies that the critics were allowed to pick Off-Broadway shows for their "Should Have Been Nominated" category for shows they thought should've gotten a nod. After all, Lotte Lenya won her Tony for an off-Broadway show.
"Some people can thrive and bloom living life in a living room, that's perfect for some people of one hundred and five. But I at least gotta try, when I think of all the sights that I gotta see, all the places I gotta play, all the things that I gotta be at"