Watson is a very smart guy and thought he had a decent, scientific answer to this question on race and crimes of sex and violence.
The Nazis used this kind of thing to back their anti-Semitic views , called "eugenics" .
Since his great discovery medical science now knows that genes must be activated by various enzymes in the body.
The genetic answer is sadly incomplete just like the old liberal idea that we could blame society or one's "environment" for criminal behavior.
For that matter nobody knows what causes a serial killer , child rapists or arsonist to do their heinous acts.
Until we get a conclusive answer, I suggest we judge people based only on their individual behaviors.
While I agree with you about judging people individually, the group data is hard to deny without going into some serious excuse making:
https://www.cdc.gov/mmwr/volumes/66/wr/mm6631a9.htmDuring 1999–2014, a general decline in homicide trends for non-Hispanic white, non-Hispanic black, and Hispanic populations occurred, followed by a significant increase in the rates for all three groups between 2014 and 2015. In 2015, homicide rates were 5.7 deaths per 100,000 for the total population,
20.9 for non-Hispanic blacks, 4.9 for Hispanics, and
2.6 for non-Hispanic whites. During 1999–2015, rates of deaths from homicide were highest for non-Hispanic blacks and lowest for non-Hispanic whites and declined the most for Hispanics.