It's also worth noting that pointing out someone's features, ethnicity, etc. is typically not an inherently pejorative thing in Mandarin. So even if they did say something that pointed out his Jewishness, there wouldn't have been an inherent racist undercurrent that there would be in English.

When I went, locals frequently said to me "Nihao wailai" or "Wairen" or some variant thereupon, they were literally saying "Hi foreigner" - and it was meant with full politeness and sincerity.

I chatted and laughed with a couple people about how saying that where I'm from would almost inherently carry aggressive meaning, but it's just not the same.