My parents had to elope. My maternal grandfather would not let his protestant daughter marry any mackerel snapper. This was in late '30's Boston where "Irish need not apply" in store windows was not uncommon. He wouldn't believe that despite his Irish surname, my father was as Anglican as him. Both grandfathers were drunks who headed dysfunctional families. As soon as they were able my parents moved away and didn't tolerate any sort of intolerance: it was a spank-able offence. Ironically my first exposure to racism came from a black man. The neighborhood in which I grew up, like many in the '50's, became largely Black with the northern migration after WW2. Most of my young friends were Black and the near neighborhood was relatively safe but the Junior High School which I was about to attend was not. As soon as the "For Sale" sign went up, Mr. Fletcher, our next door neighbor, came over and expressed to my father that he hopped he wouldn't sell to any of those real "darkies".
Because I grew up at a distance from relatives on either side and am an only child, I've not had to deal with dissension in the family. When it has occurred among classmates, neighbors, or even friends and colleagues, I normally deflect and sever the relationship if possible. Life is just too short. I'd lost all contact with family by the time my mother died 20 years ago. Occasionally I'll encounter someone like the wife of @Epigonos 's nephew. I really enjoy debating with someone with whom I share mutual respect.