the non-charitable explanation is that he's just an asshole and possibly also a racist.
the charitable explanation is that he's just insensitive and authentically wanted to make sure that the candidate would be ok with being the only black worker in his department. he certainly could have expressed himself in a less dickish way though, even if that really was his motive.
Of all the characteristics/dimensions that makes us human - why would he isolate race as a potential trigger and why is it important? Would you be equally ok with similar 'probes' for other start-up out-groups - women, LGBT, $RELIGION, left-leaners, right-leaners, weight, disablity? I mean, he could only be probing to make sure you being an Aspie won't matter to the company, right?
By the way, are you taking a shot at people afflicted with Asperger's syndrome by referring to me as an "Aspie"? It seems rather hypocritical of you if that's true.
Perhaps my outrage scale is calibrated differently, but why is it to you 'Aspie' is taking a shot, and 'Nigger' is only 'probing'?
The reason I thought "aspie" was a shot rather than a probe is because you didn't offer me a job afterward ;-)
On the flip side, I wouldn't breach the subject of religion or politics in an interview, if the topic is breached, I'm not shy about expressing opinions.
Mileage may vary, void where prohibited, quantities limited, some restrictions may apply. Batteries not included.
The USA legislates most major workplace interactions I can think of. I don't find it too surprising that people want to avoid the costly and painful legal system through whatever means they can think of, regardless of their effectiveness or ethicalness.