You are right but you forget the kids in school believe everything they are told. Everything. In my Geometry class one day I did a long proof on the board. Early in the proof I divided a quantity by zero, But the kids did not "catch" my "mistake". As the proof went on and on we ended up proving that Lines could have "negative" length, That 2= 1, and other things that were equally ridiculous. The students became uncomfortable late in the period and finally one got brave enough to protest, "But thats wrong, Isn't it?" So I told them.
As they left the class they criticised me for my un truths, while the point was for them to question authority when they think it makes sense. This was admittedly from my generation, but the question is why don't they question their teachers ideas?
You haven't dealt with 12th graders much lately, have you? They question EVERY freaking thing...