It is not explicitly implied in the sentence, which can make it harder to parse for those of us on the spectrum, but no doubt hearing this kind of comment has an othering effect for most people. The fact that you’re not as “expected” can imply you’re not part of the right group.

Racism is the structural discrimination and exclusion of certain groups of people, and this is one of the ways in which it perpetuates. If every person who isn’t white is made to feel unwelcome (even if unintentionally), is that not de facto discrimination?

A lot of this stuff goes over my head, but it is there and it’s up to us to learn to recognise it when it has a detrimental effect on our friends and coworkers.

Racism is a prejudice based solely on one's race. There's nothing "structural" about it.

The Civil Rights Act was passed in 1964. What was that for that if not addressing structural oppression?

By the whole surrounding system that treated differently and badly people according to their skin color for ages? People who say a skin color comment is just like a hair color one are delusional. Obviously there are different levels of racism, but a comment like this is already racist because it's expliciting expectations based on people's origins.

What is racist about expecting a correlation between origin and ethnicity? Would it be racism to expect Mr Wang from Shanghai or Hanako from Kyoto to be ethnically Asian?