So why is it given the TV rating of PG? The sub ratings tell the story. "V" for violence and "D" for suggestive dialogue. I suppose nothing is more violent than a super nova (except a hyper nova), but that rather distorts the intent of protecting the innocents from Game of Thrones type brutality. But "challenging dialogue," usually reserved for talk about sex?
Of course you know the reason this is challenging dialogue. It challenges the Biblical literalists. Evolution and an earth 4.5 billions years old rather than 6,000 is too much to discuss with the kids. I wonder how old a child must be before PG does not apply? Ratings are applied by the network. How must you be before Fox thinks you must be before you "question everything?"