Even Rose's article (I haven't read his book yet so I can't really say about that) tiptoes around what was going on here. It wasn't just a naive application of statistics. Rose gets through the Norma story without mentioning eugenics once, but the whole episode is so obviously part of America's pre-WWII eugenics swoon. Beyond specific beliefs about politics, race or genetics, but linked to them, there was a whole
Zeitgeist, the collectivist spirit of the age that gave us Busby Berkeley musical numbers
https://www.youtube.com/watch?v=ysvQ5MaUbd8 and the IBM company songbook
https://www.networkworld.com/article/2333702/a-history-of-si... . This was a time when it was acceptable, indeed it was progressive, to be violently hostile to difference or defectiveness: see for example
War Against the Weak https://waragainsttheweak.com/ and, maybe most especially,
The Black Stork https://global.oup.com/academic/product/the-black-stork-9780... . And of course it's no coincidence that the pioneers of statistics tended to be particular fans of eugenics themselves.
(I am not an expert on anything.)