I also don't do business in Nigeria.
The only difference being that I don't actually know anyone from Nigeria who has told me never to do business with that country.
China I know quite a few immigrants from who have told me not to and who refuse to buy anything from there if they can avoid it.
Lead in paint for toys, illegal amounts of lead in their toys, melamine in their formula, chemicals used to speed up the drying process for green tea, etc...
You raise several generations in a communist system where those who are corrupt and where you have to learn to abuse the system to survive and certain traits are going to rise to the forefront.