Cultural divides are real, and standardized testing (or crosswords) written by members of a majority culture are likely to be inaccessible to some others.
The cultural inaccessibility is not a problem, as you noted in your (now deleted) anecdote about how you don't get _Lemonade_. Not everything has to be accessible to everyone. Audiences largely self-select, and it makes no sense to attack something because the audience is all one color, and even less sense if this only upsets you if it's one particular color.
But yeah -- Lemonade was not written for me. And as I originally wrote, if it was the only record available iTunes/Spotify, I would have no cultural connection to popular music[1]. (good thing, bad thing, you decide!)
Crossword puzzle authors being only white men is absolutely culturally separate from many people.
And maybe that's OK. It's no one's job to be all things to all people. Still, it's clearly structurally unequal.
Now...whether it's important or interesting that other cultures are denied the pleasures of crossword puzzles... That's a good question. I'm of the general opinion that those other cultures are not missing much.
Crossword puzzles might just be an old white person anachronism that will fade out in a generation or two. The likelihood of that increases if crosswords are not accessible to our future majority-minority population.
[1] This is superficially relevant because Lemonade is a cultural touchstone, universally acclaimed, and (according to Wikipedia) contains elements of a dozen musical genres, more than half of which are personally meaningful to me -- and yet I found it to be inaccessible to me when it was released. Clearly I owe it to myself to re-listen.
If structural inequality is not to blame, how do you explain the discrepancy between the demographics of puzzle setters and the public at large, then?
As for measuring the demographics, well, this is a US-centric article, so the Census would be a good place to start. Or Wikipedia: https://en.wikipedia.org/wiki/Demographics_of_the_United_Sta...
Non-Hispanic whites make up about 57% of the US population. Roughly half of those are males, or around 29%.
Now we return to the question at hand: why do white men make up a very high % of puzzle setters, despite being only ~30% of the population?