with a legal English name coming out of Kenya?
Like I mentioned, every Kenyan you interact with is likely to have a legal English name. I don't see how you could stop because Americans don't really know what Kenyan names look like.
There used to be a guy named Barack Obama who would advertise, and he never got any customers
This is rather unfortunate. After Obama became president, many people in the country named their kids Barack Obama. Obama is also a genuinely Kenyan name so would you dismiss a person called Obama by pretending the name is American? If you did, I'd say you were the bigot.
(ie. Ogumbo Boubaci
Assuming this was meant to be a Kenyan name, I can say it is highly unlikely that you find a Kenyan with such a name. That someone thinks this would be more legit than say Joseph Smith is perplexing to me. Ogumbo sounds like a Kenyan last name but I have never met a Kenyan with it (I haven't met all the Kenyans, obviously).
The 'fake names' you encounter in the industry are likely to have real meanings for them. They may not be official, they may just be nicknames or English versions of African names but they aren't really fake.