Political Correctness in the Church

I'm happy with the term Sunday school. I guess “life groups” is fine for some, but I like Sunday school. I'm not ready to go to war over using Sunday school or life groups, but I do not understand changing a person's position from "sinner” to “pre-Christian.” What is wrong with the word sinner? After all “sinner” is used everywhere in Scripture. I don't see one instance in the Bible, where the word ”pre-Christian” is used.