Factoring out race is the easiest way to factor out culture. Would you not agree?
No, not at all.
On a large scale, what would be an easier way to control for so-called "black culture"?
all purchasers of the pants which size is 120% wider and 120-150% longer than wearer requires.
income. As noted elsewhere in this thread, many of the ascribed self-defeating attitudes are endemic to indigenous (>1 generation) lower socio-economic strata across the 'racial' spectrum. Yes, there are vestiges everywhere, I'd start there.