Have you all seen this post by Shyfoxling?

[sweettalkeress.livejournal.com]

I'm Dreamwidth friends with her so I noticed she was exploring Pottermore.

What she found was this.

I left a comment at the bottom of the page with my initial thoughts, but now I'm torn between that and WHYYY DID ROWLING THINK THIS NEEDED TO BE EXPANDED UPON?!

Still more credence for the theory that Rowling has the mental maturity of a twelve-year-old?

Comments

[sunnyskywalker]

Which still leaves us with the weirdness of why he picked that story. He researched ancient Muggle waste disposal (or dredged up a childhood memory, possibly of hearsay from Kendra), decided that it would make a suitably amusing anecdote and that Harry would recognize the reference, and then dangled the story in front of Harry? That's convoluted even for Dumbledore. It makes more sense as both a real or a completely made-up story if chamberpots were something in common wizarding historical memory.

[malic-ba.livejournal.com]

Is it possible that Dumbledore isn't aware of modern plumbing, and thinks that Harry would recognise the reference because that's what his Muggle family would have?
I agree, it's still a reach ...

[nx74defiant.livejournal.com]

Given the outdated condescending view Wizards have of Muggles that would actually make sense.

[sunnyskywalker]

It might! He supposedly reads Muggle newspapers, but (a) we don't know how thoroughly he actually reads them, and (b) my newspaper doesn't mention plumbing very often, so who knows what conclusions he could have formed from incomplete data. A column with an offhand joke about chamberpots might have gone totally over his head and given him the impression that we actually use the things.

[oryx_leucoryx]

Good thing he isn't a Pratchett fan, he would have called it a 'guzzunder' (that which 'goes under' - the bed), leaving Harry very confused indeed.