That is done to make their "experts," who come on at the end of the show and say that whatever they were prepping for is statistically never going to happen, that much more believable. The unwashed masses can then flip back to Dancing With The Stars with nothing to worry about.
I’ve only seen one episode of that series, but in that episode the expert analysts provided recommendations on the completeness of each person’s preparations and offered recommendations for improvement. One guy carried a backpack full of basic supplies, and planned to live on the natural vegetation that grew around the drainage canals in Los Angeles. The experts at the end of that segment said “You should think about carrying a gun for self defense.” I thought the show was going to be all about “Let’s make fun of all the wackaloon survivalists,” but that one recommendation changed my mind. If they’re going to be serious about the topic, then maybe the show is worth watching.
I have a few basic “hunker down” supplies, and I’m right on the edge of joining up with a group of like-minded folks who would band together in a defensible location during a SHTF scenario. The main problem I see in the Phoenix area is trying to defend your position and your supplies from a million starving fellow citizens. The Zombie Apocalypse isn’t quite the same when you are facing an emaciated family with a couple of kids, or maybe an infant.