We must face the fact that in Anglo American culture for the most part snakes are viewed in as threatening, cold creatures you don't want to mess with. So much so that we name fast cars after them (Cobra, Viper) and even name horrible drinks (snake bite) after them. We live in a society that uses snakes as an image of evil.
It's just part of it. But were not the only ones dog's get bad raps from locksmith company's, insects get a bad wrap from farmers and plant advertisements, Look at cute fuzzy rats they get as bad if not worse press than snakes ever thought about getting..