This is NOT true. I have at least a dozen Calkings that eat one or two small rats per feeding with some individuals able to take md. rats. I have MANY calkings that will eat more than 2 adult mice per feeding.
As with any other snake, size will have something to do with the determination of size and number of food items. Calkings can almost hit the 6 foot mark.
As far as your assertion of aggression, I have found them more apt to pee on anyone who picks them up than most snakes but not any more likely to bite.
Many babies are cantankerous and will both bite and spray liquids on you. They're afraid so it's acceptable, even amusing. 99% of them lose those antics in a very short time of regular handling and feeding.
Calkings are excellent pets.