I think part of this depends on the school. The ones I attended would completely skip sections regarding the ~1,000,000 civilian deaths during the Philippine Am

I think part of this depends on the school. The ones I attended would completely skip sections regarding the ~1,000,000 civilian deaths during the Philippine American War, the blunders in Korea and Vietnam (my classes basically said "they happened" and then the rest of the year was Civil War and WW2 movies), and there was absolutely zero discussion of American affairs in Central/South America and events leading to the Middle Eastern situation today. Schools and teachers aren't 100% standardized in America. Some have thorough history programs. Some absolutely do brush over a lot of bad parts in history, and my high school in the South was one of the types to say "The Civil War had nothing to do with slavery." Our biology class also had a huge disclaimer about evolution and how nobody had to, or really should, believe it, but they were just required to teach it. So I think when some people talk about how ridiculous/amazing the school system is, it's because that's just their experience. Schools are completely different depending on what state or even what part of town you live in.