I grew up in Texas around the same time this article speaks about. My elementary school integrated when I was in the 4th grade. It happened without incident. Back then, every elected official was a Democrat.
I’d say, the surge to become Republican started with Nixon and his promise to end the Vietnam War, and accelerated with Jesse Jackson ran for President as a Democrat and when Ronald Reagan ran as a Republican.
Ronald Reagan was the first president I voted for in 1980, and I voted Republican ever since.