My dad is racist and my grandmother is and my grandfather was. And much of his side of the family is. I grew up around it and the few times I tried to challenge it I was either out right dismissed and patronized "you'll understand when you're older" or got long lectures where I got emotional and just couldn't say the right things.
It was one of the double edged swords about going to the beach, (my dad's extended family all has houses together), the branch of the family he was closest too and we spent the most time with are really racist. Well the older generation.
Huge Rush Limbaugh fans, Fox news only, 2 of my dad's cousins are Southern Baptist Preachers that boycotted Disney. I was given Gone with the Wind as a gift and when I didn't think it was just the best ever and think the South was wronged I got mini lectured.
Then as I got older it seemed to get worse it got to the point I just spent as little time with them as possible.
Dad I've called him on stuff, but he hasn't changed. Mom, on the other hand, has gotten more accepting and open minded.
I did ask about what would happen if I ever dated a black guy and Mom pretty much said "I don't think you'd want to bring him to the beach or to meet parts of your Dad's family."
Although my dad's parents really liked and respected (according to my grandmother and to Mom) Mom's dad. Who was half Comanche. And I don't remember ever hearing racist comments about Native Americans - just almost ever other group that wasn't white, Protestant, and straight.
Besides the racist stuff I grew up hearing a lot of Anti-Catholic comments. Southern Baptists (and Southern Baptists raised Calvinist) Do Not Like Catholics. My great aunt was scandalized when she learned her future granddaughter in law is Catholic and that the wedding was going to be in a Catholic Church. At first she refused to go.