It's not a "cultural divide", it's a "representation divide", and it goes way beyond ethnicity and it's also way beyond the US.

Many institutions in the Western sphere either don't match the demographic/ethnic composition of the target market any more or never have. Parliaments, cabinets, newsdesks, movies, highest level management in big companies, even access to voting - all of this has been dominated by white, straight and often old men, with women, non-White people and LGBT not being represented at all.

Over time, many of the discriminatory policies fell - but the reality was, until maybe a decade ago, representation still lacked - and now, change is coming in ever faster and faster. You now have female-centered superhero movies, Black superhero movies, transgender people in parliaments, a Black US President... and the speed of that change was for many conservatives simply too high, so they framed the quest for equal representation across all parts of society as a "culture war" instead.