It has probably always been that way but this far removed from the War those who are teaching believe what they were taught. Most are not open to any real dialogue that may cause them to rethink it. They'd be caught between the rock and the hard place. If they did study up on it, and they did see something that shows their version to be not accurate, they'd probably fear for their position if they even allowed discussion on it. The PC Program was well set on this issue a long time ago.