those dogs are not stupid.. or most of them. most of those dogs are highly intelligent. they are problem solvers, and they don't take well to human training methods.
the exceptions in that list would be the bulldog and the mastiff or most of the mollessor breeds. as much as i love them, they are not the brightest bulbs. they also aren't incredibly trainable, it takes lots of repetition and a steady hand to teach them something that they don't already know.