But if you're just putting it in to be politically correct***, then you're bound by ideology, and that's bad art.
If you put diversity in a story just to be pc, then yes, it's likely to be bad art. There are *much* better reasons to go for diversity. Like, creating a true living world and a new perspective for the reader to sample. And the writer gets to see the world through different eyes -- isn't that one of the reasons we write?