Can't have the poisonous snakes around!! And you are so right about the non poisonous snakes.
I read something when I was looking to ID the chicken snake you see above. This site I was on said some things ~
RE: chicken snake vs rats and other vermin that it eats.... basically the rats carry many diseases that will make you sick; the snake which feeds on the rats does not harbor these diseases and if you happen to get bitten by the non-poisonous snake it will only hurt for a brief time, or if it is even able to break the skin a little peroxide will fix you up. Raising the question, which would you rather deal with, illness from diseased rats, or a possible bite from a snake that probably won't break the skin? I will choose the snake & I definitely prefer to let nature take care of itself... only problem there is the fear of snakes makes one respond in an instant manner... causing snake to lose its head.
And the fact that we will take care of us and our own first...when they start taking your food, you have a whole new fight!!
