In an interview that aired Sunday on “60 Minutes,” Donald Trump looked into the camera and announced “Stop it!” to those who are committing hateful, harassing or violent acts in his name. It was intended as a definitive repudiation by a president-elect. Perhaps he might have done better to look in the mirror instead.

Mr. Trump's decision to appoint Steve Bannon as chief White House strategist has sent an unmistakable message of approval and validation to the alt-right movement and white nationalists generally. These are the descendants of groups like the Ku Klux Klan that see the nation's “white identity” under attack by non-whites.

No doubt most Americans have no idea who the 62-year-old Mr. Bannon is. They'll see the criticism expressed groups like the Anti-Defamation League as liberal overreaction or by Democrats like Maryland Rep. Steny Hoyer or Sen. Ben Cardin as inside-the-beltway partisan politics. But readers of Breitbart News, the website Mr. Bannon took over after the death of founder Andrew Breitbart four years ago, know his brand of hate-speech well.

In the Bannon-Breitbart world, Weekly Standard editor Bill Kristol, a mainstream conservative Republican and frequent Trump critic, is a “renegade Jew,” the Confederate flag portrays only a “glorious heritage,” feminism produces “acrimony, constant suspicion and antagonism,” “birth control makes women unattractive and crazy,” and Muslims are bringing “rape culture” to the United States. It is a website that trades in misogyny, sexism and a distorted view of Islam — not occasionally or cautiously but in a full-throated, callous and frequently distorted manner.

Breitbart is surely the leading purveyor of “fake news,” its signature malice offered in the style of reporting with little regard for actual facts of any kind. One of its specialties is the kind of hit-job rumor campaign that attempted to convince readers that Hillary Clinton was desperately ill, rejecting her pneumonia diagnosis for something more likely to discourage voters like dementia or Parkinson's. The writer simply tracks down a “source,” often just one individual who will speculate wildly, and then quotes him or her liberally.

Mr. Bannon has a constitutional right to print such garbage as a form of political speech, as distasteful as it may be, but Americans aren't obligated to swallow it. More than half of the voters who showed up at the polls this year rejected this brand of politics, and if a President Trump truly wants to govern a united country, he simply can't install such a tainted individual just a few steps from the Oval Office. Even Google and Facebook have come around and have begun to recognize the problems posed by fake news on their platforms, announcing this week that they will limit ad revenues to such sites.

Make no mistake, Mr. Trump's election has already encouraged society's ugliest cockroaches to crawl out of their dark hidey-holes. As of last Friday, a survey by the Southern Poverty Law Center counted more than 200 acts of election-related racial harassment and intimidation, and the numbers keep piling up. Swastikas in a middle school restroom; people showing up at a Connecticut party in Klan costume and Trump signs; Confederate flags in a Veterans Day parade in California; a man threatening to set on fire a woman in a hijab in Michigan; an Indiana church vandalized with racist, pro-Trump slurs — the list keeps getting longer and longer.

It will take more than a few words on “Sixty Minutes” to quell this rising storm. Trump supporters can huff and puff all they want about recent protests by college students who worry about the future for Latinos, women, members of the LGBT community and others who were targeted by the Trump campaign, but their fears are legitimate. You can't disavow a pattern of vandalism and intimidation while offering a top spot in the White House to the fellow with the biggest can of spray paint in his hands.

Trump defenders say there's more to Mr. Bannon than the content of the Breitbart site. Perhaps so, but the same might be said of run-of-the-mill street vandals, too. If the president elect is willing to deport undocumented immigrants on jaywalking tickets, he ought to be willing to give the boot to Mr. Bannon for far more nefarious behavior.