So what you are saying is, yes, I am correct that Arabs are/were considered Caucasian in the US.
I did not make any mention or inference to skin color.
I replied to a post referencing a racist mayor in 1960s America that disallowed black people from living in the city if Dearborn, MI, yet Arabs were permitted.
I inferred that the reason for this was that Arabs are considered "caucasian".
I did used the term caucasian, not white.
That being settled, surely the mayor did not perform a forensic morphology exam on every individual to determine whether or not they were to be considered black. (The Biden test had not yet been developed).
Tell me, how did the racist mayor determine who was black and who was not?