I graduated in 93, so I can’t speak for what’s being taught today precisely, but I think it’s about the same, if not worse, now than it was then.
Brief synopsis of my entire 4 years of History classes in a northern New Jersey public school (as taught, fallacies included):
Columbus discovered America, sort of. Puritans settled to avoid religious prosecution in England. (Complete glossing over of the Native Americans). The Founding Fathers were gods among men. The colonies single handedly defeated the British forces (implied, but never stated, that we faced the entire might of the Empire).
(Skip a bit… War of 1812? Whazzat? Lewis and Clark who? Louisiana Purchase, huh? Manifest Destiny? Trail of Tears? Whachoo talkin’ 'bout?)
We lost at the Alamo to the invading Mexicans.
Lincoln was a god among men and ended slavery. He gave a speech at Gettysburg (we spent more time poring over the speech and how he wrote it than the events and effects of the war). The Monitor and the Merrimack fought the first armored boat battle in the world.
(Skip a bit)
WWI sucked. Soldiers got trenchfoot.
(Skip a bit)
WWII sucked more. Nazi’s annihilated Jewish populations. The allies stormed the beach at Normandy and Hitler killed himself. (No mention of Stalin or Mussolini) The Japanese bombed Pearl Harbor, so we dropped the world’s first H bombs on Nagasaki and Hiroshima, ending the war.
(Our text books glossed over the Korean War, completely ignored the Vietnam conflict, and wrapped up with Kennedy’s assassination.)
The History Channel, my own curiosity, my father’s (my entire paternal family for that matter) interest in different eras of American history, the internet, and eventually my taking a few classes at the local community college not only filled in a lot of blanks, but made me realize how much history (both good and bad) was either trivialized or completely ignored.
I learned more about American history taking American Lit classes for two semesters than I did in four years of high school.