You're conflating historical bias with a STEM field that is arguably as important as reading in modern civilization.
This is an attempt to change the political landscape in the future through indoctrination. And it will not stop here.
And let me tell you that I've been kind of indoctrinated by hardcore left wing history teachers. They wouldn't stop at teaching, they actively tried to make us think that the left was inherently good and the right bad. Sometimes it even backfired when they were exposed by someone who knew about the topic.
Hell, one of my teachers even whitewashed a terrorist group that was still active killing people back then.
This may be an extreme example but that doesn't change anything. Bad history teaching is not an excuse to bring more ideologies into school.