I had something like that some years ago. My sister has a friend called Christine, and my sister had mentioned her several times before I first met her.

Turned out that while Christine was born and raised here in Norway, she had two Thai parents.

There's not a large Thai population here, and Christine is not a name I associated with Thais, so I was quite surprised by it. Not in a positive or negative way, just plain old surprised.

I actually have one as well. At some point I was chatting a lot with a customer agent from one of our partner. To me their name sounded Russian so I assumed they were of Russian origin. Turns out they are from a Sub-saharan African country. Like you I was very surprised when I learnt it.

Given that name it IS statistically much more likely that he's white, so would there be anything malicious about that expectation?

True, but there's a difference between having an expectation and clumsily articulating it in a welcome meeting. On the balance of probability a new software developer is likely to be male and so you might be surprised that new dev with unisex name is female, but saying "oh, we weren't expecting a woman" when they walk in is obviously going to raise some very significant questions about your attitude

We make all kinds of assumptions every moment of every day. We don’t go yelling it out when those assumptions are wrong, because there’s no need to.