That's a great example. I agree. If I'm reading historical fiction I don't want to read about characters with a twenty first century mindset. Someone like Mary Renault can write the Ancient World so that her characters take slavery for granted, believe women should be confined to the house, talk about infanticide as completely normal, and that's what interesting - to enter into their mental framework. And a great writer can make those characters sympathetic, and their values comprehensible within their own context.
That was one of the problems by the end of Wolf Hall, with Thomas Cromwell sometimes sounding like Richard Dawkins (okay, slight exaggeration)My main bugbear in historical fiction is the using of 20th/21st century knowledge to prove just how smart and skilled a character is compared to everyone else. So a young and plucky 12th century physician will know all about germ theory to and get the reader on side when dealing with those old fuddy-duddies that still believe in humors and excess bile. A Roman patrician giving a lecture straight from the UN Declaration of Human Rights when it comes to dealing slaves.