Murdoch Mysteries. The story is set in the Victorian Toronto and the protagonist is a detective who employs modern forensic techniques to solve crimes. He is surrounded by barbarians who regard him as something of an oddball. We know these people are barbarians because each week some aspect of the Victorian culture we disapprove of is shoved in our face (e.g. racist, sexist, homophobic, environmentally insensitive, anti-papist or Tory).
And the One Modern ManTM happens to disapprove, too.
He has to reflect OUR biases and preferences, or we won't identify with him. I noticed this some years back when chatting with a friend who writes murder mysteries that are solved by Pliny the Younger and his faithful sidekick Tacitus. I heartily recommend his books.
If you disagree with Victorian mores, how about a society that is built upon slavery? How about a protagonist who owns slaves? A lot of slaves!
But the protagonist has to reflect OUR biases and preferences, or we won't identify with him. The hero must be the One Modern ManTM in the story. Ergo, Pliny manifests modern attitudes toward slavery.
This pattern should be kept in mind if your setting has a society with something, anything your reading audience finds revolting. In such a case, you need to make your protagonist the One Modern ManTM.