Because ads portray an image of what America is. If you can show affluent Blacks, multiracial couples and White Men as criminals or buffoons you change in a subtle, subliminal way how people think of ‘normal’ America. Why do you think so many companies now show lesbian and homosexual couples together? It’s to normalize a small minority as typical of the country’s demographics.
Based on American ad agencies a foreigner would assume that 25-30% of Americans are homosexual, almost all married couples are multiracial (BM/WF), Blacks make up around 40-50% of affluent Americans and the majority of criminals are White men.
In order for ads to shape people’s perception of America they have to reach a wide audience first. Most people I know just stream everything with adblock on.
What’s wrong with showing interracial couples or affluent black people? Shouldn’t blacks have a role model besides their local drug dealer? I’m a white woman married to an Asian guy. How does that harm anyone else?