My first thought when reading the article was: "The generous interpretation here is that whoever is fielding reports gets so many false positives that they miss true positives (like this report), especially if there's any gray area."

I'm not saying that excuses it, but it is one likely explanation for how it happened. When looking at just one report, the response seems negligent. When looking at a pile of 1000 nonsense reports, with a handful like this, I understand the difficulty.