BEIJING >> The trailer for “Doctor Strange” from Marvel Studios has ignited outrage against what some people call another example of Hollywood’s racially insensitive casting. It reveals that a Tibetan character from the comic book, the Ancient One, is played by Tilda Swinton, a white British actress.

It turns out that the filmmakers wanted to avoid the Tibetan origins of the character altogether, in large part over fears of offending the Chinese government and people — and of losing access to one of the world’s most lucrative film markets, according to one insider account.

In an interview last week, C. Robert Cargill, a screenwriter, offered that as an explanation for why the Ancient One was no longer Tibetan.

The Tibetan issue is one of the thorniest involving China and other nations. The Chinese Communist Party and its army occupied Tibet in 1951, and Chinese leaders are well aware that many non-Chinese believe that Tibet should have independence or greater autonomy.

Marvel said in a statement that there was no problem with the casting of Swinton as the Ancient One since the character was written as a Celt in the film and is not Asian at all. Some critics have said that studio executives and filmmakers must have assumed Asian actors had less drawing power than white actors.

In an interview on the pop culture show “Double Toasted,” Cargill said the decision to rid the character of its Tibetan roots was made by others working on the project, including the director, Scott Derrickson. It came down to anxieties over losing the China market, he said, if the portrayal of the Ancient One ended up stirring political sensitivities in China.

In response to an angry viewer’s question about the casting of Swinton, Cargill said: “The Ancient One was a racist stereotype who comes from a region of the world that is in a very weird political place. He originates from Tibet, so if you acknowledge that Tibet is a place and that he’s Tibetan, you risk alienating 1 billion people.”

He added that there was the risk of “the Chinese government going, ‘Hey, you know one of the biggest film-watching countries in the world? We’re not going to show your movie because you decided to get political.’”

Earlier in the interview, Cargill had acknowledged that the origin story of Dr. Strange in old Marvel comics does involve Tibet, and that his mentor was Tibetan. “He goes to a place in Tibet, the Ancient One teaches him magic, he becomes a sorcerer, then later he becomes the Sorcerer Supreme,” Cargill said.

The Chinese box office is the world’s second biggest, behind the United States, and Hollywood executives often alter films to avoid offending Chinese officials and to help their movies get shown in China. The Chinese government sets a strict limit on the number of foreign films shown in cinemas each year.

Cargill’s take on how Chinese officials and moviegoers might react to a Tibetan character was overly simplistic, though. The government and many Chinese people do not deny the existence of the cultural idea of Tibet or Tibetans. They just assert that China should rule the territory.

Cargill also said that because the original character of the Ancient One was a racist stereotype, the role would be hard to pull off with modern sensibilities. He added that if a Tibetan had been cast, it would result in the stereotypical narrative of a white hero, Dr. Stephen Strange, played by Benedict Cumberbatch, being indoctrinated into Eastern mysticism.

From the trailer, the film appears to retain some of the origin story’s Tibetan Buddhist flavor. There are shots of temples in what seems to be the Kathmandu Valley of Nepal. At one point, Cumberbatch’s hand turns Tibetan prayer wheels. Swinton’s character, though Celtic, appears to be training Dr. Strange in Nepal.

Cargill said some critics had suggested the filmmakers could have cast Michelle Yeoh as the Ancient One. Yeoh is an ethnic Chinese actress from Malaysia who is a martial arts icon and starred in “Crouching Tiger, Hidden Dragon.”

“If you are telling me you think it’s a good idea to cast a Chinese actress as a Tibetan character, you are out of your damn fool mind,” Cargill said.

Cargill also drew a parallel, saying that the only thornier situation he could envision was if Dr. Strange’s origin story had involved him going to Palestine in the 1930s and studying under a Palestinian mentor.

The Ancient One was a character who had “fallen into a weird place,” he said. “There’s a really, really ugly piece of history that we wish there was an easy solution to, and there wasn’t one.”

Cargill said Derrickson, the director, hoped that changing the gender would help offset bad choices that had to be made.

Derrickson, he said, reasoned that “there’s no real way to win this, so let’s use this as an opportunity to cast an amazing actress in a male role.”

“And sure enough, there’s not a lot of talk about, ‘Oh man, they took away the job from a guy and gave it to a woman.’ Everybody kind of decides to pat us on the back for that and then decides to scold us for her not being Tibetan.”

Swinton, in an interview with Den of Geek, confirmed that the change to the character had been made early in the process.

“The script that I was presented with did not feature an Asian man for me to play, so that was never a question when I was being asked to do it,” she said.

A Marvel press officer issued a statement defending the casting, saying that “Marvel has a very strong record of diversity in its casting of films and regularly departs from stereotypes and source material.”

“The Ancient One is a title that is not exclusively held by any one character, but rather a moniker passed down through time, and in this particular film the embodiment is Celtic,” the company said. “We are very proud to have the enormously talented Tilda Swinton portray this unique and complex character alongside our richly diverse cast.”

Cargill had a more sober take in the interview on “Double Toasted.” He likened the cultural issue involving the Ancient One to the Kobayashi Maru, a famous battle simulation game in the “Star Trek” universe that Starfleet Academy cadets must play during training. The game had been programmed so that all choices would lead to a loss.

“I could tell you why every single decision that involves the Ancient One is a bad one, and just like the Kobayashi Maru, it all comes down on which way you’re willing to lose,” Cargill said.

He neglected to mention the fact that James T. Kirk, one of the main heroes of “Star Trek,” famously did beat the game with an unorthodox gambit.