You’re explaining this to folks who are familiar with Emmitt Till!?
You can't have a healthy relationship with descendants of white slaver owners who either profited or abetted the chattle slave trade....
Or in this case, White South Africans who benefited from Apartheid....that took place a little before these people's lifetimes and their parents definitely should have warned her better.....
What someone else eats doesn't make you shyt.
It doesn't affect your life in any way, you just don't like the thought of seeing a sista being with descendents of an oppressor. The overwhelming majority of Black people date, marry, and reproduce with other Black people.
I love Black women. My mother is a Black woman and my wife is a Black woman. I would protect those women with my life.
Your opinion is your prerogative, but I think the argument that you two make is weak in validity. Just because you don't like someone's dating preferences you don't mind them getting the shyt beat out of them or even possibly killed.
That makes you no better than the people saying they don't like you because of trivial shyt like who you date, what side of town you live on, how you dress etc.
I know people are jaded and not perfect, but anarchy would run rampit and we'd be in the Wild West if everyone adopted your attitude.