I wouldn't say that snakes don't like to hang around where people are . . .
Where we our home is in AZ, it is densely populated with houses with desert nearby. We have to "snake proof" our back yards to keep 'em out. I killed a rattler with a shovel that my wife almost stepped on as she walked out and around the corner of the garage. They often come in to the yards and build nests underneath ground hugging bushes. Every year, the local Fire Dept. comes and pick up rattlesnakes that people see in their yards, street, etc. - usually the pick up and re-locate over 3,000 in a year.
No - not every snake needs to be killed. But around houses - especially where there are children or pets - they can be a big problem if not dealt with. Yes, they eat mice, rodents, etc. - unfortunately, even though it's against the HOA rules, we have folks in our development who "feed the poor birds" - and the bird food draws in the rodents and the rodents bring in the snakes.
Dealing with snakes is a "common sense" thing though - if it's far enough away that you can draw and take aim - you've got time to reverse your direction and avoid it. If you are close enough that you need to shoot - chances are that snake is going to be heading in to defense mode. The solution is - be aware of where you are walking and keep your eyes open for them - then avoid them.