Edit: Some parts of zoning law has to do with safety/health. Some parts don't. Some parts are about more than one thing.
When I was growing up there was a chemical fire in a factory in town. People were evacuated. Luckily, very few homes were evacuated because zoning laws kept homes far away from the factory. The residential area that was evacuated was low density.
The point I'm trying to make is that there is some value in some of these rules.