There is a conflict in how a conservative would look at this.
First, it is a commercial franchise story and the conservative sees this as property where the Owner gets to do with it what he will, stupid or not. Should they choose to follow a pandering whim, good luck and all that.
Secondly, we can look at the character as somewhat in the public domain. The possibility of casting a person of a different ethnic, racial, gender or style background offends our sensibilities as the character and stories are now part of our culture. Conservatives try to value what has been handed to us and protect it. Change being constant and necessary, the conservative sees the value of reform although he knows it should always be careful and considerate of empirical proofs of what works and preserves the inherited worth.
Rush is citing the second issue in his opinion, but he could be just as conservative backing the first.
You can back the first and still think it is a wrong and stupid thing to do.