Small clarification: the post's screenshot is of the News mode in Search, and not news.google.com. I think the latter is what people think of when they think "Google News". Whether the same problems are there as well, I don't know. I also notice in the screenshot that the query isn't visible, it's on page 4 of results, and there seems to be a banner saying that the search is expanding beyond the set filters. I agree…
This has a captivating headline and we've all seen the depredations in Google and elsewhere, but this is journalistic malpractice. It's not Google News, Search tells you when it is abandoning your filters because you keep infinite paginating, he intentionally cropped the screenshot as much as he could to make it as sensational as possible.
Mr. Elgan, you say this is in the "huge majority" of the time. I demand receipts. Show me just one more example, uncropped, with the full URL.