US citizens aren't fingerprinted on entry, regardless of race(!). They don't even have the fingerprint machines in the citizen line at any airport I've ever gone through, which is why I suspect GP went to the wrong place.

SFO has fingerprint machines in all lines, including the citizen lines. And in the Global Entry lines, even.

I agree with you that US citizens aren't supposed to be fingerprinted on entry, but I am absolutely unsurprised that it happens sometimes.

Every port of entry I’ve been in, they have the same setup at every booth, which definitely includes the fingerprint machines. Even Texas, though I just got waved through due to the creepy gait/face recognition thing without stopping.

Yay for our AI overlords or something?