It sounds like a term invented by the same guy who gave us "sanitation engineer" for "janitor".

I did know someone many years ago who might have deserved the title of "Multiculturally Competent". He was 'white' but moved easily in black neighborhoods and Native American groups.
He once delighted a fellow from Africa by correctly guessing his tribe from his name & accent. He simply learned what was important TO other cultural groups and managed to converse in their frames of reference. When he went to work as a social worker in Alaska, he eventually was inducted as an honorary member of a clan.

I never met anyone else who did it on that scale.