This episode is based on a commentary by Carol Ochs, from the Women of Reform Judaism website. (See Contemporary Reflection on Parashat Noach.) In this commentary, Ochs sites “miscegenation: interbreeding between the sons of God and the daughters of humankind” as a, possibly the, reason God regrets creating people and is ready to destroy Creation. (“Sons of God” = bnei elohim and “daughters of mankind” = bnot ha-adam] — see Gen 6:1-4. No footnotes in Ochs’ commentary, and no additional reference about this claim.)
She goes on to discuss Noah’s silence for much of the narrative, until after the Flood when the first words he utters are to curse Canaan (Gen 9:24-25). She writes:
So Noah’s first words neither praise God, nor express gratitude, nor ask for help, nor proclaim justice. Instead, he uses language to curse and to set up the differentiated love that will plague all the offspring of Genesis – from Ishmael and Isaac to Esau and Jacob and to Joseph and his brothers. By “differentiated love” I mean love that is given to one person and withheld from another.Carol Ochs, Contemporary Reflection on Parashat Noach
In her book, Caste: The Origins of Our Discontents, Isabel Wilkerson speaks of both endogamy and a desire to preserve “purity” as pillars of caste. The idea that miscegenation is the sin that causes God to regret humanity seems related to Wilkerson’s discussion of caste. And this concept of “differentiated love” seems similarly related. See also “Covid and Caste,” which discusses caste as it relates to DC.