Of course ABC and its parent company Disney were right to cancel the sitcom “Roseanne” after its eponymous star, Roseanne Barr, wrote a racist tweet. There are necessary taboos and essential decencies in every morally healthy society. Writing that Obama administration aide Valerie Jarrett was the baby of “Muslim brotherhood & planet of the apes” violates these in the foulest of ways.

This is not a First Amendment issue. Constitutional rights are what you’re entitled to in the public sphere, not as an employee of a private corporation. Barr’s speech has not been curtailed; she remains free to opine (and to tweet) to her heart’s content. She’s just not free to do so while getting $250,000 a show from an employer whose reputation she stained and whose values she traduced.

This is not a “free speech” issue — using “free speech” in the broader, less legalistic sense of the term. The University of Chicago president, Robert Zimmer, has made the case that institutions like his, though not strictly subject to the First Amendment, should nonetheless encourage the free and vigorous exchange of ideas for the sake of fostering intellectual excellence. That’s right. But what Barr tweeted wasn’t an idea. It was a slur.

This is not a “double standards” issue. With his trademark combination of puerile self-pity and fang-toothed nastiness, Donald Trump took to Twitter on Wednesday to denounce Disney’s chairman, Robert Iger, for not apologizing to him for the “HORRIBLE statements made and said about me on ABC.” But he’s the ultimate public figure, whereas Jarrett is a private citizen subjected to unprovoked racial attack by an ABC employee. That the president fails or refuses to appreciate the distinction is the thousandth reminder of his unfitness for office.

This is not a “one bad tweet” issue. In March, I argued that Kevin Williamson, the conservative writer briefly hired by The Atlantic, should be judged by the totality of his work, not by a vile tweet in which he seemed to suggest that women who get abortions should be hanged.

The relevant question here is: What’s the “totality” of Barr’s work, at least when it comes to political and racial questions? John Podhoretz, the editor of Commentary magazine, summed it up perfectly when he described Barr as “a boor,” a “notorious believer and propagator of conspiracy theories related to 9/11,” and, in all, “not merely a loose cannon but a MIRVed ICBM ready to go off in all directions at any time.”

Barr’s tweet about Jarrett, in other words, wasn’t the odd needle in the haystack. It was the last straw.

What about the argument that liberals use another double standard when we applaud Barr’s dismissal while defending the rights of football players who take a knee to protest police brutality during the singing of the national anthem? The players don’t have unrestricted First Amendment protections while wearing the jerseys and playing in the stadiums of the teams that pay their salaries.

It’s true the players don’t have the legal right. But they have the moral one, especially when their gesture is dignified, and when the NFL has blurred the lines between commercial interests and the totems of American patriotism. To love freedom is to exercise it. That is not a function of standing for a song.

Barr has exercised her freedom to tell us what she thinks — but without the virtues of dignity and consideration. Iger and the ABC Entertainment president, Channing Dungey, exercised their freedom in denouncing her tweet and canceling her show.

To their credit, Dungey and Iger appeared to be acting on moral principle, and not merely surrendering to the verdict of a social-media mob. That’s an important distinction. The intelligent defense of free speech should not rest on the notion that we must tolerate every form of speech, no matter how offensive. It’s that we should lean toward greater tolerance for speech we dislike, and reserve our harshest penalties only for the worst offenders.

Also to their credit, Dungey and Iger acted despite “Roseanne” being a ratings hit. Something mattered more than a bottom line.

Let’s hear from Trump supporters on this — presumably, something other than the muttered excuses and tendentious whataboutism of a political movement that is capable of saying and doing anything except look itself in the eye.

— Bret Stephens is a columnist for The New York Times.