Yeah, I don't agree with Sarex here but cfr is a tad biased towards buffing the US' reputation. Middle quintiles is not the recognised definition of middle class, well, anywhere; middle class is top quartile, in terms of income. That's a really basic mistake to make, though my evaluation of cfr is poor enough that I suspect it isn't a mistake, but is a deliberate. Their data actually shows most recruits come from blue collar and working class. Though really that's exactly what you'd expect (along with a lot of people from military families) since those are the largest demographics.
This also makes a nice comparison with the Russian losses map and illustrates exactly how propaganda works. The cfr map of military recruitment uses absolute numbers to show that poorer states aren't over represented in the US. Guess what happens if you use absolute numbers on that Russian map? You guessed it, Moscow turns black, Tuva turns green and suddenly it's ethnic Russians seeming to die disproportionately. Which is as unsurprising as California, Texas, Florida, New York and other high population states contributing most recruits to the US military, and Moscow has something like a fifth of the Russian population.
Always smelled like a psyop that.