Threats of libel claims do not only lead to things not being published which should be published.
Such threats can also lead to things being published which otherwise would not be published.
I understand a recent edition of a significant UK publication carried an article primarily because the writer threatened a libel claim over a poor book review.
I have read the article in question and I can confirm that it reads more like a Craig Brown or Alan Sokal parody than a serious piece of intellectual writing. In my view, it probably would not otherwise have been commissioned, let alone published.
I understand the writer got away with this demand because of the ease with which even a negative book review can be the basis of a defamation claim under English law and the sheer cost of defending the claim.
The reader of the publication, however, does not know this and would suppose that the article would have been commissioned in the normal editorially-sound way.
This is the state to which English libel law has brought responsible journalism.