Most of the time, the teachers DON’T See those parents. Because they don’t need to.
Which leads them to the false belief that those parents don't exist, and to the hubris that they (teachers) are smarter and better educated than most parents.
And that's where we are today: Parents are finding out that the teachers are teaching racism and perversion, and calling a halt to it. Teachers like the critter in the OP are shocked to find out that their self-image of superiority is unfounded. They're shrieking in horror, denying the obvious.