Forgive me if I'm misunderstanding what you're saying, but it seems to me that you've got it backwards. "Moor" is an anglicization of Maurus, the word of a Mauretanian in Latin. It long predates Islam, and was always originally applied to the inhabitants of Mauretania in northern Africa

I don't think it has. Most dictionaries hold with the North African definition in first place.

"Moor" is a word that has a lot more historical baggage than actual modern utility. It's useful for describing a period in the history of Spain, but when in appears in English usage the meaning is often inconsistent. For example, the title character of Othello is described as having thick lips in one part and as coming from the Barabary Coast in another.