I was actually raised in midwest GA during elementary years and north GA from then on. I never saw an uncut cock in the locker rooms in school when I was growing up. The schools I attended had a very low percentage of African Americans, and from what I have seen as an adult, most of my black buds around here are uncut, so that probably would make the statistics more in line with what you are quoting. However, I never saw a white, uncut cock in my circle of peers while growing up. Even now, and I'm in my 50's, I have only seen one uncut white cock in my gym locker and steam room....and I've seen a lot.
I had a similar experience growing up. My black friends were about 1/3 uncut and the rest cut (born in the late 1960s), but I didn’t see a white guy my age who was uncut until I was in my mid-teens and saw one guy at a Boy Scout camp.
And then I saw a few guys my age who were uncut at college or in graduate school, but still most were either black, foreign exchange students, or the sons of first-generation European immigrants.
Interestingly, the bulk of the uncut black guys were from what sociologists call the Black Belt, where freed slaves lived after the Emancipation Proclamation and the Civil War—a semicircular geographic area stretching from Maryland down the coasts of the Carolinas, through Georgia, and around to the Mississippi Delta.
And about half the black guys from Texas.
NCbear (who learned, years after high school, that one white friend hadn’t been circumcised; in PE classes, we had always been encouraged only to change our outer clothes, not our underwear, and we didn’t have time for showers afterward—I only saw a lot of cocks growing up because I went several summers to a Boy Scout camp with open showers and several other summers to programs for academically gifted kids at universities across the state; others saw a lot of cocks because they were on either the football or basketball team [the soccer team didn’t have access to the football showers after practices or games])