I am not disputing that some form of wild rice was cultivated in Africa. In fact rice is a grass and grass grows everywhere. What is questionable is whether its foundation as a commercial crop began in Africa. Also, not sure where you got your information of rice in Africa 6000 years ago. Please reference this article, it says China was the origin.
Your original scream was that cook up rice couldn't be "black man food" because according to you blacks knew nothing about rice before Indians arrived.
In your simpleton ways you dont consider that one pot dishes with rice are popular among black communities from South Carolina all the way down to Brazil, so yes consumption of rice was known long before the first Indian indenture walked off the plank in British Guiana.
The rice was clearly NOT being sourced in India or China as the transportation of that era wouldn't have permitted it. In fact rice was grown in South Carolina and elsewhere and shipped to the Caribbean slave plantations, together with salted meats and corn/wheat flour. Ground provisions and plantains were grown in the Caribbean, hence your illogical notion that this is the only foods that blacks knew about.
In fact the African rice was of a different species than the Asian so in fact its YOU who need to thank the Chinese for their rice. Africans had domesticated the varieties that they found there.
Given the different settlement patterns and the lower population densities Africans had no need for huge plantations as did the Indians and the Chinese. Their economies were based on producing what they needed and buying what they couldn't produce. Their trading partners in North Africa also had rice so there was no need to sell it to them.
The issue with African vs. Asian rice is this. During the colonial era cocoa, coffee and palm oil were the commercial crops, not rice, so all of the focus on improving rice varieties that occurred under the FAO and other organizations was focused on the Asian varieties. So today the Asian varieties are higher yielding whereas the African varieties remain relative unchanged.