Think about this.
Talking about school text books:
"And this goes on everywhere. It is political correctness. There is no way to solve it ultimately. But I think it's good if you get some pushback from the parents, particularly since the teachers, who generally are the ones who have sway over this, are left-leaning and you get a lot of liberal slant in the textbooks. "
Now why is that? Why are the majority of teachers left-leaning? Because they graduated from university where the professors are mostly left-leaning. And why is that? Think about it.