The vast majority of them were voted out at the next possible opportunity as well, so theres that.
A few weeks ago, it was implied that Mr. Biden was a racist because he said that when he first was elected to the Senate, he was able o work with all those segregationists running that body of the time.
He was first elected in 1973.
All those guys never switched over and continued remaining in the Democratic Party. They left the Senate either because they died, or retired (perhaps because they stood no chance of winning).
The south was a reliably Republican voting bloc long before Reagan, and WAAAAAAAAY before 1994 and the Contract with America, so you're gonna have to bring something better than those as proof of concept.
The south had begun swinging Republican in the 1950s (you know, before the CRA). On the presidential level, Republicans won a few times in the south ('64, '72, '80, '84 and '88), but otherwise votes tended to be split-- Democrats were elected to Congress, state and local governments. That began changing in the 80s and 90s.