My guess would be that pretty much everybody knows that this mental model is wrong, which is why the author considered it appropriate to jokingly play naive, because just calling it "bizarre" felt too weak.

You are not.

When you charge a battery you are pushing electrons from one chamber in the battery to another. A discharged battery is like two tanks of water at equal levels, charging is like pumping water from one to the other so one has a higher level and thus potential energy.