“You’ll find that in the Arabian peninsula there are people who are known as “True Arabs”. This was the cultural heartland of the territory where the Arabic language was developed.
There are surrounding groups who have been Arabicized.
Anthropoligists and historians differentiate between the two.
Then, there’s a far larger group surrounding these people where Arabic is spoken. And beyond that, there’s a vast territory where Classical Arabic is taught for the purpose of reading the Koran.
Members of the Luo tribe who are Moslem are simply part of the vast hinterland where Classical Arabic is taught for historical purposes.
Culturally the Luo are Luo!
The Luo also appear to have Negroid characteristics ~ nose, degree of pigmentation, shape of skull, hair structure.”
Luo, though, has a connection with Indo-European and Semitic languages in the pre-Ice Age period.