Am I overreacting about my grandma's anti-American attitude?

My Grandmother was racist towards blacks. We come from a family who owned slaves and who live in the South. She never treated anyone rude and only shared her views with family. When my Uncle contracted polio and almost died he had a black nurse. This lady loved my Uncle and would comfort him when my Gramma had to leave. He would call both women Mama. That was the beginning of the end of my Grandmother being racist. She still thought whites and blacks shouldn't intermarry...then my Uncle met a women he fell in love. True story...he found out that women was the daughter of his nurse. Who could argue them meeting wasn't a miracle? There went that belief. She still beleived that a mixed couples should not have babies...she held her great grandson for the first time...there went that belief. She doesn't talk to her brother anymore because he could not see the beauty of a new life and could only speak vile words...we love my Grandmother. God has a funny way of breaking down berriers. Just love her. You don't