Every high school I've taught at, or that's been in the same district, has shit History departments. Usually one, or two at most, dedicated history majors teaching. The other "history" teachers are coaches. We know how much the US cares about their stupid sports teams.
This has been going on since I was in school decades ago, and definitely continued throughout my career. I've watched teachers pulling their team kids into little discussions where they talk about some bullshit game that they had or are about to have. I've watched these idiot jocks get pulled out of academic classes to go to games on a weekly, or more , basis.
The decades of shit education in civics and history, coupled with obvious conveying of shit values, has definitely led to a nation of ignorant assholes. The scary thing is, this is something that will take a decade at least to fix, when/if the schools ever recognize the problem. Too late.