As a kid who grew up in 70's in the Gentile South, it's laughable to think the republicans (or any organization really) wasn't virulently racist. Our parents had attended segregated schools, ate in segregated restaurants, and among the family stories were anecdotes of Granddaddies' slaves and the "War of Northern Aggression". Along side fields there were small wooden huts that previously were inhabited by sharecroppers and slaves before them. Cities, towns, and geographical features are named after large plantations that long since disappeared into modernity.
So, In my lifetime, we can dispense with the fallacy non racist republicans.
As for change in the republican party, It's clear that you lucky lot didn't grow up in the shadow or the 700 Club, CBN university, Gerry Fallwell, Daughters of the Confederacy, Edgar Cayce and the like.
The dark rise of the Costco Republicans brought religious and ideological purity tests to the party and perhaps more importantly brought politics fully and openly into the churches. The ultimate synergistic grift fusion. Churches used to mince around political issues for fear of losing their tax exempt status... That concern has been wiped away. The culture war is on baby, and Jesus prefers AR.