Answer:
Islam in W. Africa was simply a consequence of trade, unlike Christianity in China. The comparison, I believe lies in the relative spiritual needs of the elites in both places. Chinese elites had rejected Buddhism for the most part, and Confucianism alone leaves much to be desired with regard to spiritualism. Chinese lower classes benefited from a blend of Buddhism/Confucianism.
In W. Africa, it was the elites more than the lower classes exposed to Islam because trade was the social engine, and well regarded, and elites participated. The lower classes on the other hand had less exposure and were content with the ancient animist traditions extant in W. Africa.
We can see a similar trend in the recent history of the West. Upper-class, more educated, people are increasingly secular, while religion tends to remain the enclave of the lower and working classes.
Explanation:
