With all that self-important writing, George Will carefully avoided stating what it was about Murray's "Bell Curve"' that upset so many people then and now--his claim that black people were less intelligent on the average than white people.
As far as eugeneics, yes, this was a very popular movement among both conservatives and "Progressives" "back in the day", and some terrible mistreatment of so-called defectives, including required sterilization, occurred.  But lest we forget, that was back before birth control became common and available-- and many social thinkers were horrified at seeing the large and often miserable families of the very poor.
  The frequent childbearing was destroying the health of the mothers, and the infant mortality rate was incredibly high compared to today.
However, it was the Fascists and not the Progressives who carried this concept to its ugliest extreme in simply destroying all those the system regarded as inferior, often starving them to .death.