In my experience the only folks who pretend Oklahoma and Texas aren’t southern are some Yankees who’ve moved there for work and have superiority complexes
As usual
As proof.....drive from leave Texas or Oklahoma into New Mexico or Colorado or Kansas and watch the accent change at state lines
And sweet tea disappear
Or go to almost any county seat square and tell me why that CSA statue is there
You know I had barely been on this forum a month when a Yankee in Houston lectured me Texas ain’t southern
Lol
And Oklahoma. I got books on Oklahoma as southern stock
That Grissom guy
Census bureau as well
Again the accents don’t lie
When I moved from Texas to Oregon many years ago, I was asked if I brought my six-guns and horse with me ... based on my accent ... :-) ... I don’t know what’s happening with my accent, now, since I came back to Texas, and then Oklahoma.
I’ve always considered Texas and Oklahoma to be part of the South, but I have noticed that, at times, there were others who didn’t.