Even if they were, I'd imagine somebody would mingle with a black person with longer history and more of a mix. To me that much purity represents insulation and older roots not recent ones.
How accurate are these things anway? How is any of this verified/proven
Nigeria is a colonial creation. There was not such country called Nigeria when his ancestors were there, because the Country of Nigeria was not created until 1960. So that Nigeria result is a score for not only Nigeria, but also for countries around Nigeria. Some of the people in Togo, Benin and Cameroon would also probably come back with Nigerian scores, because many of them are from the same area but when White people cut up the land in smaller countries some people were just in different countries. So the Yoruba people and Hausa people are not only in Nigeria, but they are also in Benin and the other countries around modern day Nigeria.
23andme has something called an ancestry timeline that lets people know the estimated range of birth years that people had an ancestor that was 100% from a specific country. It is guesswork, but Nigeria comes back as one of the significant regions for African Americans for having recent ancestors within the last 150-200 years. The significant thing about that is that the Yoruba people were having a civil war after after Oyo Empire collapsed and the Yoruba began to throw each other into slavery. Dahomey had also began to slave raid in Yorubaland in modern day Benin and in modern day southwestern Nigeria. Additionally the Aro Confederacy (who are Igbos in the Cross River region of Igboland) began slave raids into northern portion of Igboland, which is in southeastern Nigeria. The Aro Confederacy was raiding and kidnapping the Igbos who lived in and around Onitsha, Owerri and Enugu, where they burned down villages and sold captives to American ships that docked down river in the Bight of Biafra. That went on until 1860, which is important because that is when the American Civil War started and it is also important because those people were brought directly to the USA. It is also significant that it was American ships that were purchasing slaves, because it was illegal to import slaves directly into the USA after 1808. The reason for that ban was because the USA had just purchased the Louisiana territory from the French and the new plantations were opening up down river. Virginia planters wanted to sell their slaves to the new planters, but they were selling the slaves at a premium price that the new planters could not afford so the new planters and their Wall Street backers began to smuggle slaves into the USA from West Africa. That went on for period of 52 years from 1808-1860, which why people were still being kidnapped in modern day Nigeria up until 1860 and it only ended when the American Civil War started. If you all are interested in this subject then there is an excellent book that you can read called:
They smuggled so many people into the USA from West Africa after 1808 that they don't even know how many, but some people have estimated over 100,000 people. African Americans high Nigerian DNA results along with their most recent ancestor indicates that is probably true. The dynamics of the American and Nigerians of that period was just crazy and the American government swept all of it under the rug, because many politicians, business people and wealthy people were involved in the smuggling. Here is more information from the Igbo side and where the Aro Confederacy was raiding, which included as far east as Northern Cameroon.
https://digitalcommons.calpoly.edu/cgi/viewcontent.cgi?article=1012&context=hist_fac
