In an interview, he told his story wasn't racist on purpose ; he truly believed that was how black people were based on the very few informations he had at the time - he never traveled outside of Belgium.
When he made the next one with a chinese person, he contacted a student who was originally from China to educate himself on how Asia really was, the culture, the people, etc. And that's how he came up with one of the best books of this career.