Fighting Prejudice

I feel compelled to write about this experience with my two eldest sons and their father, regarding a man I was in a relationship with years after the divorce.

The man I was in a relationship with was from Morocco and had an Arabic name.
My ex-husband is a bigot. The boys were around 4 & 6 years old at the time.
Once day they came home from spending time with their dad and the 6 year old asked "Mommy, what's a sand n-word?" Of course, my heart hit the floor as I prepared my answer. It felt like my answer had to be good and that it shouldn't directly attack the person who had introduced this hateful term to my son. 

I also needed to answer so that a 6 year old could understand, so I said "it is something mean that someone says about another person that they don't know and they don't like." I had to say that it was a 'mean' word. Keep in mind that my son wasn't telling me who taught him the term. After a short pause, my son asked matter-of-factly, "How can you not like someone that you don't know?" It seemed to be an epiphany because he figured out that his father's attitude toward their mother's friend didn't make sense.
I used this story in my geography class today when talking about Islamophobia and xenophobia. Who would have thought I could use my ex-husband's racism and ignorance to teach high school students about xenophobia?