Elanor. Kudos to you. You have called it exactly. Men believe that women of their "tribe" are their property and are being "contaminated" by men of other "races." That is why white men feel obliged to intervene in public arguments between white women and their non-white partners, and men of other groups do the same with women of "their race" and their partners. The author came close, but you have absolutely captured the bull's eye that is both racism and patriarchy. Good thinking.