Fans can’t fault the new “Upstairs Downstairs” on “Masterpiece Classic” (8 p.m. Sunday, PBS, check local listings) for its period details. As mentioned earlier in this space, I think the melodrama sometimes seems too “ripped from the headlines,” as they used to say about “Law & Order.” Or at least ripped from the history pages.

While “Upstairs” immerses itself in a nervous British society in the waning days before World War II, I get the feeling the writers have projected too many 21st century attitudes on the characters.

Prevailing social attitudes in prewar England (and America) included widespread acceptance of racism, anti-Semitism and huge chasms between classes — particularly among the aristocratic set. This was years before the dissolution of the British Empire, the rise of America’s modern civil rights era and the end of socially accepted anti-Semitism on both sides of the Atlantic. And it was certainly light years removed from modern attitudes toward homosexuality. That was punishable by imprisonment.

But in tonight’s “Upstairs,” we have Lady Agnes (Keeley Hawes) carrying on a blatant flirtation with an American Jewish businessman, even appearing in an ad campaign for his company’s nylon stockings, and doing so without her husband’s knowledge or his blessing. Is this really 1939?

Members of the royal family breeze in and out of kitchens and seem chummy and at ease with staff not their own. Blanche (Alex Kingston) suffers few serious social (never mind legal) repercussions after her former lover writes a book about their lesbian affair.

An “Upstairs” shot through with the bigotries of its era would probably not be so entertaining. But overlaying our generation’s attitudes on historical figures is dicey as well. It reflects an unwillingness to see the world from the perspective of another people from another time.

Sunday’s other highlights

• The Denver Broncos host the New Orleans Saints on “Sunday Night Football” (7:15 p.m., NBC).

• The San Francisco Giants meet the Detroit Tigers in Game 4 of the World Series (7 p.m., Fox).

• No guts, no glory on “The Walking Dead” (8 p.m., AMC).

• Dexter investigates the murder on his boat on “Dexter” (8 p.m., Showtime).

• During an Easter gathering, Eli tries to regain Nucky’s confidence on “Boardwalk Empire” (8 p.m., HBO).

• Corporate ways do not sit well with Janette on “Treme” (9 p.m., HBO).

• Brody feels confined on “Homeland” (9 p.m., Showtime).