I have a hard time to find critic on what they do. In the end, what is it? Independency. Freedom. No reliances. Help yourself. I don't see any doom involved in this.
Lots of differences between a 'prepper' and a 'doomsday prepper'. I predict there will be plenty of natural disasters to survive before "The Big One". What with storms taking out power supplies, floods cutting off food supply and fires threatening your homes there are plenty of reasons to have a torch with plenty of batteries, a supply of drinking water, enough pasta and rice to last a week and a 72 hour grab bag. Even if you never need them it gives you confidence.