Rattlesnakes are FAR more common than most city slickers/animal rights advocates think.
They are quiet when you are at a distance and blend into their environment almost perfectly. They are also pretty darned good at finding places to hide.
Even if you know what to look for and are good at finding them there are almost certainly more out of your reach than are within your reach.
Out on the ranch they tended to kill them on principle because of the danger to the livestock as well as a strong desire to never find them in the house.
That being said I never really felt the need to shoot them unless I was in personal danger. I see the guys who hunt them for a living as about half nuts, surely there are ways to make the same amount of money without repeatedly handling creatures that are that deadly. Different strokes I guess.
Gaily bedight, A gallant knight In sunshine and in shadow, Had journeyed long, Singing a song, In search of El Dorado