You can't say it's obvious unless you can point to something it is specifically lampshading. The best answers I've seen so far in this thread are that it's lampshading itself, in which case there's no reason for it to have been in the story. Traditionally when you hang a lampshade on something, it's something that the author needs as a plot device but actually wouldn't make very much sense if the story were playing out realistically, that is, it threatens suspension of disbelief. I don't think any of us would disbelieve that Dumbledore would have a strange vroopy thingy in his office, so lampshading itself doesn't make any sense (which I suppose would make it a meta-lampshade, which breaks the suspension of disbelief I have that the author is trying to use a trope in its proper context, and such abstractions could recurse infinitely).