I've been confused by economics in this way too.

I'm not confident enough to say that it means something's wrong with economists, but I can never tell where the assumptions come from. The way I was taught in school, if the professor was a Rational Expectations guy, he would teach the course as though Keynes had never been born; and vice versa. It was like the blind men and the elephant. Very disappointing. I could have used an aerial view.