BuzzFeed, under Mr. Smith, has built up a fine traditional news team that has won journalism awards precisely because it succeeded in the ultimate purposes of its craft: to establish fact from fiction and enhance its readers’ understanding of reality. That’s the opposite of pumping out a bunch of unsubstantiated allegations and then leaving it to readers to “make up their own minds” about them with no reportorial guidance.

You can argue that the dossier was going to get out there anyway. But it hadn’t until BuzzFeed published it, even though many news organizations, including this one, had the dossier for months. And had they leaked by some other means, it would be up to journalists to establish their veracity; ignore them if possible, debunk them if necessary.

That’s what BuzzFeed has done with its top-notch reporting on the “fake news” phenomenon, helping to shine an early light on the false stories so many Americans were sharing on Facebook and other social media platforms throughout the campaign.

But every journalistic misstep gives more fodder to people who want to stop the efforts against “fake news” by turning the tables and labeling those efforts — or any other solid journalism they don’t like — as “fake news” as well, corrupting the term for their own purposes (a classic case of “no, you are!”).

That’s what Mr. Trump did Wednesday morning.

In calling BuzzFeed a “failing piece of garbage,” Mr. Trump gave it a cri de coeur. But there was collateral damage: Mr. Trump’s “fake news” charge against CNN, in front of many millions of Americans, went directly at the network’s core purpose as a global news provider.

CNN drew Mr. Trump’s hostility by breaking the news on Tuesday that a former British spy had compiled the Russia dossier and that intelligence officials included a synopsis of it in briefing materials for the president-elect. Once CNN opened the door, BuzzFeed followed by publishing the document itself.

But as CNN pointed out, it did not share the details of the memos, and it did not even link to the BuzzFeed report, despite false claims to the contrary by Kellyanne Conway, Mr. Trump’s adviser. Its decision, the network said, was “vastly different than BuzzFeed’s decision to publish unsubstantiated memos.”