I don't know if John Key really did describe the resignation of Pansy Wong as a 'tragedy,' as I heard mention in casual conversation. The context in which I heard it was taken as meaning he felt it was sad a corrupt minister has been found out and forced out of office. Perhaps that's what he really does think, under the smooth charm.
But, if Key did say it, regardless of the sense he intended, he's right. What has befalled Pansy Wong is a tragedy, the Shakespearean sense, where a character who has some admirable qualities is undone by some intrinsic flaw in their nature.
Alas, I don't think the arrogant presumption that brought Wong down is limited to her. I think it is rife in our political players, and this tragedy will have many more acts, and a bewildering range characters vying to be the protagonist. It's an unedifying spectacle, and should be booed from the boards.