I don't like to kill snakes because they eat mice and rats, but if it's a rattler or if they are killing animals of mine I suppose they gotta go because they are territorial, but I won't kill one just because it's a snake.
I even leave rattlers alone if they are not hanging out in an area I have to traverse regularly, but if it's coiled up on my porch, sorry dude, but I don't want you that close to my house and I have no assurances you won't keep coming back even if I am stupid enough to try to risk contact to relocate you.