I understand some part of his family is Moroccan but think it's wrong for people to just assume they're not from the country they represent just because of their name. Otherwise we'd never call someone like Bukayo Sako English.
I mean, I have an Irish surname, but I've lived all my life in England
If I decided to declare for England and had come through an English teams academy, you wouldn't class me as an Irish player if Everton signed me FFS and I reckon you'd get some extraordinarily odd looks if you did
So classing a demonstrably Dutch person as an Arabian just because of their surname seems pretty rum to me. I'm sure he's proud of his heritage but he hardly came straight from the desert to the Feyenoord youth set up you know?