Why you should never kill a Black snake

The snake feeding looks like a Blue Indigo. They are a dark blue black color with a white underside with hues of red and yellow. Very pretty. Had a pet one when I was a boy in central Fl. They introduced them into the Orange groves to keep rattler population down.Very calm snake would wrap around my cowboy hat and go around with me. when people tried to touch him tho he would bite the piss out of them. State of Fl. has them on the protected list.