Well, it's not "wrong" to balk at seeing the world from a different point of view than the convention dictates. What is "wrong" is any insistence that the conventional view is the correct (or "right") one. Moralizing is never a good thing, but it is quite in order to criticize attitudes that equates an upside map to an upside cup, or to evil mindsets, such attitudes are widespread. It's an invitation to accept that our conventions are - conventions, not truths. How "something can look so wrong and yet not be wrong at all" doesn't come naturally, it has to be learned through examples like this.