It's morally wrong to hate something for an attribute they have no control over.

Is it morally wrong to hate someone who chooses to drink? Not really.

Is it morally wrong to hate someone born addicted to opioids, or born with fetal alcohol syndrome? Of course.

Being born "foreign" is no different, especially if you, as this chef does, live in a country where "nationality" is coterminous with "ethnicity" to the point multi-generational immigrant groups (ethnically Korean Japanese, for example) are considered "Not Japanese" by many Japanese people.