There are problematic and poorly researched ideas in the book and defending it is just douchey no matter how polite and professional you think he's being.

Getting Istanbul wrong was still stupid no matter who did it.

The problem with the Arab thing is that Sara's father (who I'm guessing from context lives there/works there/is a professor of Turkish literature/a grown-ass man/in general somebody who should know better) also refers to Turkey as an Arab country and they say this in front of Turkish people like Amesh without anybody bothering to correct them.

I'm sure at least one guy in Turkey has a turban for some reason, and that some Turkish people have unusual names, and that at least one woman has been in Turkey wearing a niqab, but if there are fifteen different unlikely incidences that pass largely without comment, the net sum is an inaccurate portrayal of the country.

I don't see any particular reason to doubt that she's a Turkish woman who lived in Istanbul at some point and currently lives in San Diego. Hell, she could have immigrated six months ago, we don't know that. Although I don't see why we have to scrutinize her background. She identifies with Turkey and feels personally slighted, and she obviously knows what she's talking about far more than the editor and the author do. She doesn't need to prove she has some kind of advanced Turkish cred to be right.