The video is a very short news item about FEMA testing the emergency alert system this week, but that's not what I thought people would enjoy. It's the comments - people are going batshit insane with every conspiracy theory you can think of (and more that you never would).
I suppose there is fear of it being abused (think 1984 telescreens you're unable to turn off)? There was a test recently here in the UK and we had the same fears discussed. The noise was pretty awful so I just turned it off, but maybe people don't realise you can disable it.