I don't get why Texas is seen by some as a Deep South State. It see it as part of the Southwest like Arizona, New Mexico, Nevada, and Colorado not like Arkansas, Louisiana, Mississippi, or Alabama which is Deep South territory. Does Texas's or Texas A&M's affiliation with the Deep South ly in College Athletics because Texas A&M plays in the SEC and Texas A&M and Texas played in the old Southwest Conference with South Carolina and Arkansas up to the early 1990's when both moved it to the Big 8 or Big 12? Is it because of politics because the state of Texas is a GOP stronghold along with rest of the Deep South States?
The western part of the state (El Paso and everything west of the Pecos River) is obviously very southwestern/western, as is the Panhandle. But very few people live in those areas of the state. Most of the population and economic activity is in Central and East Texas.
I do agree that while you can call Texas part of the South, it's inaccurate to call it a
Deep South state. I confine that term to Mississippi, Alabama, Georgia and South Carolina.