I agree with Mykee. Its people just passing off bad info, and old ways of doing things sticking around .
My BF has a great grandmother who was always taught snakes should not only be avoided as a bite from certain ones meant sure death way back when, but also to kill any near human dwellings. This sounds monsterous to us today, but frankly that's the only way they knew back then and a snake bite, while very serious now (from hots) was MUCH more serious 50+ years ago. And sometimes things are just "beaten" in so to speak to the point its hard to see a snake otherwise.
Personally we do not try and argue or change her views as she is old, and we respect the way she had to grow up. But that's just one person. On a whole the only thing you can do is keep giving out CORRECT information at every turn.