US-based rattlesnakes probably have a monopoly on the killing of absolute morons, as a result of snake-handling religious people. Cottonmouths might rival them, because their placement in the US Southeast exposes them to a lot of fucking imbeciles.
Coral snakes, because of their pleasant disposition (they'll often allow children to handle them without biting!), probably kill a disproportionate number of idiots. To be killed by a coral snake, you have to be such a fucking idiot that you're basically playing with a deadly animal until you accidentally hurt it.
Black mamba kills probably can't be parsed by IQ. Like, those fuckers are just nasty and don't really give you a chance to back off. Australian snakes would be similar except only Australians live in Australia, so those guys probably kill a lot of morons.
Not really sure where I'm going with any of this.
Snakes are dangerous.