Maybe we need to go easy on the OP- If I only read the subject line, he just asked a question and I would bet that while a lot of hosts notify guests of bad weather, a lot do not.
That being said, this discussion comes down to a no-win scenario and that no good deed goes unpunished.
Hosts doing this probably do disturb two kinds of people- those who are self sufficient and well aware of the situation and didn't need someone meddling in their business and those who are just plain grumpy and don't care.
The host has their own concerns- If they are smart, they know the odds of the campground getting destroyed are small and that they are meddling and bugging self sufficient folks....but what about the one time a campground is hit...heck, I'm sure THEN someone would sue them for FAILING to notify folks.
So they are damned if they do and damned if they don't! A no win scenario!
And additionally, I don't see this as any crime of the century- so if you are self sufficient and don't need a do-gooder- too bad, you shold politely accept the meddling. And if you are a host- what choice do you have- Live dangerously and let the folks sleep, or if the storm does destroy the campground- live with the fact that maybe some folks might have benefitted from the warning.