Corporate America has drawn a red line around criticism of the teenage activist survivors of the Parkland massacre–but the sanction for crossing it only applies when it comes to conservatives.

Hulu, TripAdvisor, and more than a dozen other companies pulled their advertisements from Fox News’s Ingraham Angle after host Laura Ingraham tweeted last week that Parkland survivor David Hogg was “whining” about getting rejected from certain colleges. But when Joan Walsh, a paid politics talking head on CNN, tweeted a sarcastic remark at Kyle Kashuv–“good luck with your stress”–no advertisers pulled ads from CNN.

Two differences stand out. Ingraham is an outspoken conservative advocate while CNN’s Walsh is a left-winger. And Hogg is an advocate of gun control and vocal critic of the president, while Kashuv is a defender of the Second Amendment who recently made a friendly visit to the White House.

In other words, this appears to be a story of corporate America siding with the left wing against conservatives.

Many of the boycotting companies say they are applying a non-political standard. TripAdvisor said it pulled its ads from Ingraham Angle because it did not “condone the inappropriate comments made by this broadcaster.”

“In our view, these statements focused on a high school student, cross the line of decency. As such, we have made a decision to stop advertising on that program,” a spokesperson for TripAdvisor told Breitbart News.

TripAdvisor did not respond to requests for comment about whether this standard would apply to the comments of CNN’s Walsh.

At least eighteen companies have pulled their ads from Ingraham Angle, many tweeting out statements about joining the advertiser boycott. These include Hulu, Wayfair, Nutrish, TripAdvisor, Nestle, Bayer, Johnson & Johnson, Expedia, Stich Fix, Jenny Craig, Office Depot, Atlantis Paradise Island, Liberty Mutual Insurance, Progressive, Miracle-Ear, Principal, and Honda.

Clothier Joseph A. Banks was initially reported to have pulled ads from the program but denied those reports to Breitbart News.

None of these companies has said they would pull ads from CNN.

A similar pattern emerged when Kurt Eichenwald, a journalist widely thought to be a contributing editor to Vanity Fair, told Parkland survivor Kyle Kashuv, “I have no respect for you.” All of the companies joining the anti-Ingraham boycott fell silent.

On Tuesday, a spokesperson for Vanity Fair said Eichenwald was not a contributing editor. This apparently came as a surprise to Eichenwald, who claimed that he had never been informed that he had lost the post at the magazine.

–Amanda House, Sean Moran, Matt Boyle, Penny Starr, John Binder, and Ian Mason contributed to reporting this article.