Cultural diversity is a crucial vector for human progress
Even if there are many intermediate levels, we can broadly distinguish two trends: popular cultures and elitist (or erudite, avant-garde) cultures.
The most popular cultures tend not to encourage a sense of openness and therefore do not encourage people to think independently. When people lock themselves into standardized centres of interest, they are no longer in a position to understand the complexity of political issues, and this is a perfect breeding ground for populist political excesses. This is particularly obvious with screen culture, especially as the internet is expressly programmed to offer no diversified content.
In the case of elitist cultures (which reach far fewer people), there are generally two types of audience: modest classes of intellectuals and artists, whose political aspirations are predominantly progressive, and classes of economic elites whose aspirations are predominantly conservative (there are, of course, many mixed levels). However, these two apparently opposed worlds are very often linked by culture, especially in the rich countries of the West, which develop many policies to support culture and the arts. The majority of artists are inspired by and identify with progressive and humanist socio-political movements, and their aesthetic influence on the conservative elites also allows certain ideas to be distilled, even if this takes time, whereas a large majority of the population often doesn't feel concerned by these principles. This is probably at the root of paradoxes about the origins of certain social advances that would not emerge simply from a popular democratic balance of power (for example, openness to issues of sexual liberties and identities, abolition of the death penalty, ecology, etc.).
This is why I believe that promoting cultural diversity by fighting against the omnipresence of commercial cultures is also a way of encouraging humanist progress.
Image from the film Do Not Expect Too Much from the End of the World, Radu Jude, Romanian, 2023