“How did “African” got on there?”
The parents.
“African isn’t a “race” “
It is in Kenya. From the 1962 Kenya Census Form,
“Column 5. Race.-Write European, Arab, Somali or African, etc. Asians must write Indian or Pakistan.”
http://www.hist.umn.edu/~rmccaa/IPUMSI/CensusForms/Africa/ke1962ef_kenya_enumeration_forms.en.pdf
So would Obama Sr. consider himself “African”.