I see the Chronicles of Narnia like the Bible, the Koran, The Canterbury Tales, Don Quixote, The Scarlet Letter, or Huckleberry Finn. We can look at great literature as emblematic of its place and time. We can enjoy the writing, the stories, and the lessons we can learn from them without saying we want the real world to be like the one in the stories.
Banning books - like all censorship - has never ended well. I learned that lesson from other books. A couple of them are Fahrenheit 451 and The Rise and Fall of the Third Reich.
What is clear in ALL the stories of censorship: It is never the good guys who propose censorship to protect people from "bad ideas."