The anger of public responses in the buildup to Oprah Winfrey’s interview with the Duke and Duchess of Sussex Sunday is a sign of the growing chasm between the generations, say expert royal watchers and social analysts.

Rarely have divisions inside the royal family engaged such a cross-section of society, or range of ages, inflaming opinion among those who normally pay little heed to dramas played out at Buckingham Palace.

This time, in addition to old questions of authority, class and privilege, the row concerns race, identity politics, gender, loyalty and patriotism. And when the interview goes out in America, before being aired around the world, including the UK, on Monday, the arguments will reach an audience on a grand scale.

“Anthropologically it is so interesting, and that has always been my concern really,” said Robert Lacey, author and royal adviser to Netflix’s hit series The Crown. “In a secular society, they [the royal family] are the closest thing we have to religion. Down the years, they only matter if they matter to people – and clearly they still do. That is why Harry and Meghan are going on primetime television in America.”

Social media, with compelling episodes of The Crown and the sustained popularity of Meghan Markle’s former television show, Suits, mean that younger observers on both sides of the Atlantic feel they are still relevant.

“There is great appeal this time for young people,” added Lacey, who has been writing about the royal family for 40 years. “I’m also enormously struck by the differences between American and British reactions. It’s quite extraordinary how Americans see it solely as a question of the Sussexes ‘finding freedom’. Whereas here we still tend to accept you will be restricted if you are a member of the royal family.”

Heightened concern about the treatment of a black American by a traditional British institution has also had a powerful effect. A special broadcast this morning from Westminster Abbey to mark Commonwealth Day on Monday is to go out in Britain ahead of coverage of Winfrey’s interview, to underline the royal family’s commitment to former colonies and to social issues. The Duke and Duchess of Cambridge will be shown talking to South African doctor and health activist Zolelwa Sifumba about the rights of healthcare workers.

Speculation about the motivation of the Sussexes has prompted admirers of the Queen, often those who have watched her down the decades, to blame the younger couple for a lack of respect. Yet for young people, Meghan and Harry often represent a welcome modern brand of openness and a brave refusal to follow outdated rules.

“Meghan is like Diana in so far as she is a divisive figure without necessarily intending to be,” said Penny Junor, biographer of both the late Princess of Wales and Prince Charles. “But there is a generational divide now too because more younger people probably feel she is a victim, while older people don’t see it that way.” Junor added she feels “such sadness” that Britain has lost the Sussexes.

“Harry brought so much sparkle,” she said. “I was there in Windsor for that amazing wedding and I was so pleased that this woman was marrying Harry and was going to bring something so much more relatable into the royal family. There was such public goodwill on that day, it’s so sad it all soured.”

In the countdown to the interview with the self-exiled duke and duchess – a show sold to 68 countries and is due to attract a bigger audience than the Super Bowl in America – reactions to the split between the Windsors have revealed changing attitudes to codes of public behaviour and to the establishment itself.

The instinct of Deborah Mattinson, director of the consultancy BritainThinks, is that age will prove a key predictor of how someone views this conflict, although evidence is anecdotal. Mattinson’s research for her book Beyond the Red Wall, about changes to traditional working-class views in northern England, indicates that older Britons in that region maintain a strong connection to the concept of a dignified royal continuum. “My work suggests that older voters in those locations are very pro-monarchy and the Queen – and this is integral to their sense of patriotism,” Mattinson said.

Lacey has traced a long, unpleasant thread of social disdain for women who marry into the royal family, but it is coupled with an odd ambivalence. “Catherine [Middleton, now Duchess of Cambridge] had to run the gauntlet of snobbery – and the Middletons to some extent still do. Even with Diana, although the public loved her, they also disliked sides of her.”

Royalty remains a British USP and a major cultural export, whether repackaged for television drama or used for diplomatic soft power. Centuries of schisms and scandals suggest that, whatever the era, the royal family has never been a comfortable place to be. As the underpinning for a system of deference and privilege, it will always be the centre of attention. And the human discord that surrounds the monarchy is also likely to go on for as long as it does. Only our reactions as commoners will change, as society moves on.