I would agree that US text books, particularly for high school and earlier are hopelessly corrupted with revisionism and whatever the current political emphasis happens to be.

I wouldn't argue that at all. The issue is that grade school and even high school level history classes (well, social studies) are trying to convey the basic lay of the land without adding so much detail as to be over the head of those they are teaching.

So, yes.... simple narratives are given. But they are narratives that one can build on and add too as once gains more experience and information. This is often emphasized to students..... who since it doesn't effect them much, mostly ignore it. The kids just want to know enough to pass the test, and so they ignore the qualifiers. Then 10 or 20 years later they complain that "I was lied too" when that didn't happen at all.

People often choose what to remember from their own lives, and would even sometimes reject video evidence proving X-event from their live happened very differently. This same thing happens with what people think they were taught, choosing instead to remember an even simpler narrative then what they were actually taught.

The classic example people like to scream about is Columbus being hailed as a the guy who Discovered the New World. And yes, that's basically poetic license being somewhat misapplied. As he couldn't discover someplace that already had people living there.

So, then it becomes Columbus was the European who first sailed to the Americas. And that's not even fully true, mostly cause of that pesky Lief Erikson. But the Erikson journeys were not all that significant in their own time. And they were brief and didn't really go much of anywhere.

We know this because disease didn't go rip through the New World after that 1000 CE contact. The reasons for that are several.... mostly having to do with (1) Northern climate in Newfoundland, which itself was (2) an island (somewhat isolated from the mainland) that was somewhat sparsely populated by natives. Natives that for the most part (3) stayed away from the Norse who showed up. Those three factors coupled with the short duration of contact saved a bunch of Native American lives.

Where as the disease vectors take off pretty immediately when it comes to the Spanish contact in the Caribbean and then in Mexico. Hot weather, lots of natives, and everybody fairly willing to jump into bed with each other pretty quickly. And then for the Spanish to then use those disease epidemics to their advantage when it came to conquering the New World. (Conversations that probably went something like this: "So, hey there..... while your coughing your guts out I would just like to make sure were all in agreement on who's is charge around here now?")

As you can see, these things get very complicated rather quickly. So, yes.... schools have a tendency to teach very simplified narratives in the early years. It's not out of malice of trying to push a certain story for political reasons (most of the time), but is just born of the effort to keep things easy to understand.

The mistake people make is in assuming that they are every taught the full 100% detail about any subject. They aren't. This is true for history, math, English, science, health, music, art, even PE. There is always more detail to learn.