I said they bite only in defence and for food. Not just for food. The cats may have tried to kill it, and it bit them to defend itself. Cats will often jump at anything that moves. It's why you can "play" with kittens by swinging a mouse on a string. But no, most wild snakes aren't even venomous, it's just that people think they are. Most snakes you run across aren't venomous, they just look like them to protect themselves. Granted, it's quite easy to tell them apart, but most people just say "Snake!!!!!" and pull the trigger. They don't really care one way or the other, they think all snakes are dangerous and evil. But garter snakes are good at getting rid of locusts (the flying grasshoppers that eat crops, not the thorny trees) and other ahrmfull insects, and they will eat small mice. Larger snakes, such as black snakes, bullsnakes, and hog-nosed snakes eat mice and rats, and keep their populations low or almost nonexistant. Copperheads and rattlesnakes eat mice, rabbits, rats, and other small, harmfull pests of crops. None of these snakes will chase people, and most will try to get out of your way. As you said, most snakes are caught and "milked" for their venom, to make anti venoms. But this is changing rapidly, as scientists study the components of the venoms, some of which can be used for medical purposes. Such as the compound in copperhead venom that is very good at stopping breast cancer from growing and spreading to other areas of the body. But many of the snakes that they get the venom from are wild caught, and then released. They don't keep many snakes in captivity, as it is much easier to collect them from the wild, milk the venom, and then release them. This keeps the cost of collecting the venom low, and thus the cost of the final product low. And it takes many snakes just to get a small amount of venom, and it takes a good amount of venom to get a small amount of the final product. So, most of the snakes they get the venom from are already "out".
