I remember thinking this about Europe when they taught us the continents.  My disagreement persists to this day.  Europe and Asia are obviously the same continent and the distinction between them is arbitrary.  I would guess that this easiest-to-accept of lies, since it is of no consequence to one's daily life, would be a particularly good starting point in the indoctrination scheme.  These sorts of lies could gradually be added over time until we arrive at the bigger ones that relate to philosophy, the physical sciences and economics.

In retrospect, I can also note that my teachers' responses to these questions about the trivial matter of the European "continent" sound awfully similar to the responses I was given when questioning inconsistencies between the Bible and what we were taught in church school, or when I challenged my mother on the existence of Santa Claus.  All of them essentially amount to "just do what I say."  The one that bothers me the most is the Santa Claus thing, because it's so near and dear to people's hearts.  It's a very well crafted propaganda tool used to generate conformity.  I've never seen a better one for at least singling out what you refer to as Mustangs in this series.