It’s not a “whistle.” Culture is virtually co-extensive with ethnicity in most places in the world. I come from a country whose name literally just translates into “country of $ethnic_group.” To the point where the largest country in the world, China, has lumped myriad different populations into the ethnic grouping of “Han Chinese” to cultivate cultural uniformity.

I'm not sure what the complaint is here. I don't mind saying outright that I believe ethnicity is deeply intertwined with culture and that the two concepts are inseperable. Ethnic groups are essentially defined by their shared heritage, experiences and culture. When we talk about cultural diversity, we inevitably also discuss the ethnic diversity of a population.

I really don't think that is a controversial position, but clearly you disagree.