I agree. I do feel that temperament has everything to do with age and handling. Hatchlings have to defend themselves but as the grow up and you aren't looked at as a threat they calm down. It takes longer to get an "aggressive" adult to trust you. But with time, gently handling and an occasional bite, they learn you aren't out to get them. I've had several snakes considered to be unhandleable that after time calmed down.
It would be an interesting study to see how/if temperament can be inherited in reptiles.