The links at the bottom are gray, which fools the unwary that editing is possible.
They're always grey, actually. Just like the grey edit links beneath your question right now. We don't use grey links to indicate unusable links - we simply remove the links in the first place.
For actually empty tag wikis, you get a giant "Create Tag Wiki" button. It's only in this scenario, where there is an edit pending which prevents a new Tag Wiki from being created (much like how a post is edit-locked with a pending suggestion), that the button isn't visible.