Plagiarism is a serious offense, but it's a private matter within our profession.
A reporter who scrupulously attributed every fact, quote, or turn of phrase would run the risk of missing her deadline, exhausting her available space, or turning off her audience with her cluttered prose. In such cases, chastising a journalist for plagiarism is like criticizing a policeman for running a red light in pursuit of a mass murderer. Incidentally, I write as a journalist whose work has often been plagiarized. In one case an author re-worked a magazine article of mine, without attribution, into a chapter in his book. In another case an author cobbled together an entire book largely from articles I had written, again without attribution.