I may or may not have been a teacher, both at the high-school, community college and college level in a previous life, but I can say with 100% certainty that this type of thinking is pervasive. Most teachers aren't as blatantly stupid as this gem, but they infuse their bias throughout all their lessons......whether it's mathematics, english, social studies, philosophy, etc. It's a constant and steady drumbeat and, hate to say it, fuck, it's hard to counter on our own with just the family unit, friends and select media outlets to provide different viewpoints.
Just have to keep fighting in our ways.