The Reagan's "11th Commandment" thing is a myth.
Reagan was the only Republican in modern history to challenge a sitting GOP president for the GOP presidential nomination and he did it because Ford was a liberal.
Try reading this some time and you will see that Reagan DID NOT give politicians a pass because of an "R" after their name:
If Reagan hadn’t won the nomination in 80, who do you think he would have voted for in the general election?