You see, zealous and rebellious Jews were responsible for the deaths of thousands upon thousands of Roman people. So, here amongst this scenario, you have the spread of Christianity. So that's what they did. Roman bishops and pontiffs, etc. So, there came the Laws against Judaizing on Saturdays, and the Orders To Keep Sunday.
History is peppered with writings expousing Anti-Jewish sentiments.
The potential beauty of the True Sabbath was squelched.