I disagree. Arabs are considered Caucasian in some parts.
An anecdote: Egyptian friend studies abroad in the US, gets arrested visiting New York state for very overdue parking tickets he was unaware of (studying elsewhere in the US). They bring him to the station, and the cops attempt to fill in the paperwork, and they admit to my friend they are not sure what to fill in. In the end, they look in their procedure book, and said he is Arab and that is considered a subset of Caucasian in their definition. I was actually surprised by this.
Whether Arabs are caucasian or not is not GP's point: it's that someone who was born in Africa, and lives in America, can fairly consider themselves to be African-American, just on that basis.
An anecdote: Egyptian friend studies abroad in the US, gets arrested visiting New York state for very overdue parking tickets he was unaware of (studying elsewhere in the US). They bring him to the station, and the cops attempt to fill in the paperwork, and they admit to my friend they are not sure what to fill in. In the end, they look in their procedure book, and said he is Arab and that is considered a subset of Caucasian in their definition. I was actually surprised by this.