I think that's in large part because often many others will pile in by referring to the newspaper that ran it. I wouldn't count that in same class, as they're often "technically" not wrong in that they're reporting that "according to X, Y happened" rather than making the false claim that "Y happened".
The fake Hitler diaries would be one of the really major examples of this, where Stern, Newsweek and the Sunday Times ran the primary stories, and lots of other publications ran stories about the stories in those three.
And that's also a major example of the main sources taking a lot of flack afterwards, with firings, lawsuits, and books and movies about it afterwards, but it's not clear if it actually harmed the newspapers themselves. E.g. Murdoch has suggested the Sunday Times actually profited from it in the long run as Stern paid them back what they paid for access, and it boosted their subscription numbers even after the hoax was revealed.
>it's not clear if it actually harmed the newspapers themselves
As long as 1.) it's a rare event and 2.) the publication gives the appearance, and perhaps the reality of, throwing the guilty and those in the wrong place at the wrong time under the bus, putting better processes in place, apologizing profusely,and being very introspective about the whole affair, people tend to forgive and forget--or at least forget. And their peers probably have at least a bit of "there but for the grace..." about the whole thing anyway.
I'm being a bit snarky about throwing people under the bus. Usually there are people who are guilty mostly in a "the buck stops here" sort of way. But, in most of the recent cases I can think of, there were individuals in the news organizations who so wanted stories to be true that they were at best inept in a way it's not clear they understood even in retrospect.
The fake Hitler diaries would be one of the really major examples of this, where Stern, Newsweek and the Sunday Times ran the primary stories, and lots of other publications ran stories about the stories in those three.
And that's also a major example of the main sources taking a lot of flack afterwards, with firings, lawsuits, and books and movies about it afterwards, but it's not clear if it actually harmed the newspapers themselves. E.g. Murdoch has suggested the Sunday Times actually profited from it in the long run as Stern paid them back what they paid for access, and it boosted their subscription numbers even after the hoax was revealed.