I grew up in Texas schools in the 70's, 80's, and graduated in 91. We were required to take whole history classes in middle and high school that was nothing but "Texas history". Stephen F. Austin and the old 300 (which included one of my ancestors) James Bowie, the last stand at the Alamo and the defeat of "Santy Anny", on and on. I even went on to win a whole-ass state level UIL history competition for a play I wrote about it.
I did not learn until I was a big grown up girl the real reason.