Genetics?
LOL! What? Dont overthink it, Mr. Peterson. It’s called an ideology not geneticology.
He’s referring to the degree to which personality is inherited.
And given how social justice warriors and other liberals actively refuse to associate with conservatives, the scenario in the young adult dystopia “Divergent” books with everyone with the same personality essentially segregated and intermarrying actually looks plausible.
Only you’d have less “switching” after the first two or three generations, and the people kicked out of castes as nonconforming wouldn’t be breeding divergents because in that system they were too poor to have families.