My feelings are that yes parents say stay away from snakes....true. That's a generalization.
But parents who aren't interested in reptiles have no obligation to explain every single species and proper handling methods to kids if they happen to come across one in the backyard. Its safer for most parents (who are not reptile educated) to tell their kids to just leave all snakes alone.
I agree parents who teach kids to kill living things is sick, but I do not believe every adult or child on this planet has an obligation to understand how all species effect the ecosystem, and if they are venemous or not. Its up to each individual to fear snakes or not.