Because people don't understand how smart they are. Things need to make sense to a donkey, they aren't just willing to obey blindly. So you need to be smarter than the donkey in order to train them. read more
Things need to make sense to a donkey, they aren't just willing to obey blindly. So you need to be smarter than the donkey in order to train them. That qualification tends to limit the pool of potential trainers. read more
The same reason pigs and cows are also known for stupidity: human ignorance. In reality, pigs, cows and donkeys are quite intelligent. Most people just assume that they are all stupid. As for stubbornness, some people regard that as a virtue, because they call it persistence or perseverance. read more
Donkeys are infamous for one thing, their resistant to taking orders from people. This might be what contributes to why people think they are dumb. read more