In my HS social studies classes, we would discuss current world news and events, part of which was the current ongoing Desert Storm war of the early 90s. We talked about the Patriot Act and it's contents, and the reasonings for or against it. But we didn't talk about how good or bad Bush was, only his actions and decisions.
We also had a separate Civic studies class, which focused on government operation and logistics, both current and historical.
Social studies classes weren't partisan, part of class was just discussions of current events. We were also 14-18yo, not 4, and not being taught to sing some idiotic song ripping on the sitting PotUS.
If a teacher did this same thing, but calling Trump bad, it'd be just as depraved and pathetic. Four year olds should not be exposed to this, they obviously aren't going to be thinking about the things they're saying/singing. THAT is indoctrination.