Most Americans tread lightly in discussing ethnicity and religion, and we do it so habitually that it's nearly unconscious. Some might call this dishonest, and maybe it is, but it also holds moral truth: until you've walked in the shoes of other people, you can't really grasp their frustrations and resentments, and you can't really know what would and wouldn't offend you if you were part of their crowd.
The Danish editor's confusion was to conflate censorship and self-censorship. Not only are they not the same thing, the latter is what allows us to live in a spectacularly diverse society without the former; to keep censorship out of the legal realm, we practice it in the moral realm. Sometimes it feels uncomfortable, but worse things are imaginable.