BEIJING — When the “Doctor Strange” screenwriter C. Robert Cargill offered an explanation for why Marvel Studios had cast the British actress Tilda Swinton as an important Tibetan character from the original comic book series, he started a new controversy surrounding the film.
In an interview last week on the pop culture show “Double Toasted,” Mr. Cargill had tried to quell a growing uproar from critics accusing Marvel of racism in casting a white actress in a role that they said should have gone to an Asian actor. The trailer, released this month, showed Ms. Swinton playing the Ancient One, who in the comics is a Tibetan mentor to Dr. Stephen Strange, the protagonist.
On “Double Toasted,” Mr. Cargill said that filmmakers had decided to scrub the Ancient One of his Tibetan origins. And that was, he said, largely because Marvel executives feared any depiction of Tibetans and Tibet could anger the Chinese government and the Chinese people, putting the studio at risk of losing access to the second-biggest film market in the world.
(Asked to respond, Marvel said in a statement that the Ancient One was Celtic in the film but did not address the China-related issues that Mr. Cargill had raised.)
In recent days, commenters on social media have continued to criticize Marvel — some for the casting of Ms. Swinton in what they said should have been a prominent role for an Asian actor and others for what they called the studio’s sycophantic attitude toward the Chinese Communist Party. The anger was especially pronounced among Tibetans opposed to Chinese rule and their supporters.
Jigme Ugen, the president of the Tibetan National Congress, wrote on Twitter:
On Wednesday night, Mr. Cargill said in an email that his remarks on “Double Toasted” did not represent Marvel. He wrote:
I’ve made a lot of mistakes in my life, but none that I regret as much as choosing to answer a question to which I had no place in speaking. I tried to make it right by clarifying my position on Twitter Monday but unfortunately — perhaps ironically, given that this story gained so much steam on social media — those comments were not picked up by those reporting on my statements from the original podcast. Those original statements were my own personal musings about a character, and although I worked on the film script, I came to the project after the first draft and was not part of any casting discussions or decisions so I had no right or knowledge to speak about them as if I was. It was a moronic decision, and worst of all, I embarrassed my friends and colleagues by coming across as if I were speaking for them. I was not.
Mr. Cargill sent the email from Austin, Tex., where he lives and has worked as a film critic. Austin has a tightknit film community, and Mr. Cargill wrote about movies for Ain’t It Cool News, an influential website started by Harry Knowles, another film fan in the city. He became a successful commercial screenwriter after his script for “Sinister” was made into a hit horror movie. The director and co-writer of that film was his friend Scott Derrickson, who directed “Doctor Strange.”
Here are Twitter posts by Mr. Cargill on Monday, which aimed to clarify his comments about the Ancient One. Posting under @Massawrym, the handle he used on Ain’t It Cool News, Mr. Cargill wrote: “FOR THE RECORD: no one at Marvel or with the film ever talked to me about China, so contrary to headlines, I didn’t confirm anything.”