The Fourth of July wasn’t strongly celebrated until the 90s (after Gulf War I) in the small southern town I was living in during the 80s/90s. Something about still being bitter about the Civil War (which we were taught was not about slavery, but states rights, ugh).
The states rights thing is pervasive. I was taught the same thing in a public school all the way up North in Michigan. (late 90s, early 2000s)
Yes, the Civil War was about states' rights. Yes, the South was fighting for independence from what it saw as Northern political bias and Federal overreach. But all of those ancillary issues were about defending slavery as an economic and cultural institution.