Last night, the Penske Media Corporation became the news rather than simply its conduit. Jay Penske, the CEO of the media conglomerate and son of billionaire Roger Penske, fired David Velasco, the editor in chief of one of his new properties, Artforum.

Penske axed Velasco, who has worked at Artforum for eighteen years, after the editor published a letter signed by thousands of artists calling for a cease-fire in the face of Israel’s onslaught against the Gaza Strip. Apparently publishing artists’ concerns about violence against civilians — what one might describe as an airing of those concerns in some sort of “forum” — was not actually Velasco’s job.

Artforum’s publishers wrote a statement last night saying that Velasco violated the magazine’s standard editorial process, but reporting shows that the ouster followed campaigning by advertisers and art collectors who objected to the letter. As the Intercept writes, shortly after Artforum put up the letter, “Martin Eisenberg, a high-profile collector and inheritor of the now-bankrupt Bed Bath & Beyond fortune, began contacting famous art world figures on the list whose work he had championed to express his objections.” He was aided by influential gallery owners, whose response Artforum published, as well as by another letter, which fails to mention Palestinian deaths and garnered thousands of signatures, including from tear-gas salesman and art world figure Warren Kanders. At least one Artforum staff member resigned today in response to Velasco’s firing.