Why homeless people prefer live behind Walmart?
Walmart allows travelers with an RV/camper/trailer to spend the night in their parking lot. No, they aren't supposed to live there permanently. They also aren't supposed to sleep on the ground, in tents, litter, set up outdoor camps, piss in the parking lot or shoot heroin.
Never heard this or seen it
Never heard of this before...
I was homeless for around 7 years, and I can tell you bluntly that camping behind a Walmart would be a HORRIBLE place. Often what encounter behind the Walmart is more Walmart. Their parking lots extend for quite a distance. Police also often frequent Walmarts, and they'd chase you off for sure. Like someone else said, if you owned a car then Walmart might be ok so long as you move around, but you'd never find people sleeping against the back of their store.
I've literally never heard of homeless people living behind Walmarts. Maybe this is something local to your area; like a homeless encampment in the woods behind a Walmart? On the other hand, if you are homeless and own a car, Walmart may be ok as they almost never bother anyone parking on their property overnight. This is why you often see RVs and sleepers in their parking lots. Just shift between Walmarts in the area, and you'll have a 'safe' place to park each night.