In a pivotal scene from “Hidden Figures,’’ based on the lives of three African-American women who played integral roles in America’s early space race, a white NASA supervisor is shocked to learn that a black female mathematician must sprint to the other side of campus to use the “colored’’ bathroom. Disgusted, he marches toward that restroom and, with a crowbar, smashes one of the most familiar emblems of the Jim Crow-era South.

Unfortunately, this rousing moment is as phony as the Bowling Green massacre — yet not at all uncommon in Hollywood films. In “Hidden Figures,’’ a movie where African-American women are the clear heroines, the filmmakers still felt compelled to make up a white male savior who literally strikes a blow against 1960s segregation.

Without fail, such unnecessary scenes are condescending, insulting, and patronizing to their audiences, regardless of race.

When I saw the movie, I wondered about that moment’s authenticity. It seemed too symbolic, too much of a salve to comfort audiences after more than an hour of racism both subtle and overt. And, of course, it was. Also fictional: the gruff but fair NASA boss Al Harrison, played by Kevin Costner, as well as the scene when he personally invites mathematician Katherine Johnson (played by Taraji P. Henson) into Mission Control to watch John Glenn’s historic flight, made possible by Johnson’s eleventh-hour calculations.

Here, the notion behind these convenient fictions is as simple as it is cynical: to put white filmgoers in the soothing presence of a “good’’ white character, and to show people of color that not all white people, even during this nation’s most turbulent times, were racist.

Some moviegoers had a similar complaint about “12 Years a Slave’’ when Brad Pitt suddenly appeared as the film’s only kind white character, an abolitionist. It was as if, after so much cruelty at the hands of white slave owners and their co-conspirators, Pitt allowed white audiences to finally exhale.

Theodore Melfi, the director of “Hidden Figures,’’ defends the feel-good fairy dust in his film. “There needs to be white people who do the right thing; there needs to be black people who do the right thing,’’ he told VICE News. “And someone does the right thing. And so who cares who does the right thing, as long as the right thing is achieved?’’

By that logic, one of the black women forced to use the offending bathroom should have been given that cathartic release — except everyone knows she would have been hauled away in handcuffs. A white male savior is one thing, but a black avenging angel is a “right thing’’ too far.

When a film claims to be “based on true events,’’ it’s a veracity disclaimer. It means while some scenes are accurate, others eschew history for narrative purposes. No one goes to such a film expecting a documentary. Yet Hollywood does itself no favors by bleaching African-American stories with white saviors. It plays directly into this nation’s reticent relationship with its own racism, and its persistent need to soft-pedal it. Stories about black strength and perseverance against bigotry are dulled to assuage white guilt. Never mind that a greater statement could have been made about our past if, after Johnson’s genius saves Glenn’s flight, she were shown not in Mission Control, but watching the launch on television, which was all she was allowed in real life.

In several scenes, Johnson is shown running, even in a driving rain, to the “colored’’ bathroom, though she never did that. In Margot Lee Shetterly’s book, on which the film is based, Johnson says she was never asked to use a segregated bathroom, and she didn’t. Racism doesn’t always reveal itself in a thunderclap of segregation; more often, it involves the kinds of small indignities that gnaw at the soul and psyche everyday. Not cinematic, perhaps, but closer to the kind of facts that this nation still can’t quite grasp.

A box office hit and a multiple Academy Award nominee, “Hidden Figures’’ is an act of historical restoration, but also revisionism. Until Shetterly’s book, the achievements of Johnson, Dorothy Vaughan, and Mary Jackson remained in shadows; at last, they are getting their long-denied recognition and acclaim. Yet, like so many films before it, it comes with a sleight of hand that lets Americans indulge white mythology and sugarcoat their nation’s past.

Renée Graham can be reached at renee.graham@globe.com. Follow her on Twitter @reneeygraham.