Dear Participant,
The civil rights bill prevents businesses from discriminating. Free commerce was more or less exclusive to the Reagan Presidency. The two do not really make for a binary concept.
What changed in the discourse is that White America feels discriminated against. This allows a style of presentation that was foreign to the Conservatives of yesteryear. But I think you meant that in recent decades the Republicans have been up front about repealing regulation. Though they still believed in the rule of law. Some regulation is always needed. And now thirty years too late, Congress is getting around to doing their job.