Weird questioning at US customs

US citizen returning from Mexico and the US customs agent points to my last name on my passport and says “Ukrainian?”. I say “no, American”. He goes “Doesn’t look American to me..”. I just shrugged and said “it is American”. The he gave me my passport back and let me through.

Has this happened to anyone else? They should have all my info on the screen unless they’re asking about my ancestors.. it just made me feel weird!