No, it doesn’t.
Google: the avoidance, often considered as taken to extremes, of forms of expression or action that are perceived to exclude, marginalize, or insult groups of people who are socially disadvantaged or discriminated against.
Wikipedia: The term political correctness (adjectivally: politically correct; commonly abbreviated PC) is used to describe language, policies, or measures that are intended to avoid offense or disadvantage to members of particular groups in society.
Merriam-Webster: a belief that language and practices which could offend political sensibilities (as in matters of sex or race) should be eliminated
Cambridge: avoiding language or behavior that any particular group of people might feel is unkind or offensive
Collins: Political correctness is the attitude or policy of being extremely careful not to offend or upset any group of people in society who have a disadvantage, or who have been treated differently because of their sex, race, or disability.
False. A teacher’s job is to teach. Teaching about the Earth and Moon are part of the curriculum: they are a part of science.
Teaching about Santa Claus is not. Not in first grade, anyways. Maybe in a mythology class.
I also note that you ignore that this was a substitute teacher. Their job is to teach what the teacher tells them to teach. If you read other reports, you find that it was an announcement, not a lesson. And that the substitute went on to reveal that other parts of childhood mythology are not real, like the Easter Bunny, the Tooth Fairy, and so on.
And then there’s the simple aspect of “Why was she reprimanded if she was just doing her job?” You try to blame it on PC, the Santa story far predates the rise of the PC movement.
She got in trouble because it wasn’t her job.