The ancestor sold donkeys, and the son inherited his father's business!
But... Donkeys are so cute, how can they eat donkey meat!
So it can only be sold to people who don't eat donkeys!
"As big as the world is, there are always people who don't eat donkeys but can use them!"
"You will starve to death, my silly daughter!"
"When I become the king of the world, I will issue a ban on donkey meat!"
"... You are going to let our family be punished by the nine tribes!"