Everything you're saying would be true if it was the journalist themselves doing the alledging. But the journalist is quoting a source through paraphrase, and t

Everything you're saying would be true if it was the journalist themselves doing the alledging. But the journalist is quoting a source through paraphrase, and the source is doing the alledging. It is not libel to say "An anonymous source said [libelous thing.]" Because there is no claim made through that statement that what the anonymous source is saying, is true. The only claim being made through that statement is that that claim is in fact what the source said. If the anonymous source wasn't anonymous, maybe they'd be guilty of libel. But the journalist isn't. They're just reporting on the libel someone else is committing.