It So True Its Sad!
A similar situation happened to my cousin who married a Central American Woman with Taino Indian features. At the Wedding I was standing with my Dad to the side talking about how nice that everyone came to the wedding. When my cousin's Uncle a childhood friend of my Fathers who grew up in Spain, with some drink in him came out his mouth and said "You see! There he goes messing up the family blood by marrying a Indian!" My Father quickly stopped him from talking because my Dad married a Puerto Rican and me being his son I'm technically mixed.
My father was so pissed about that that he told his friend to kindly not to say that about his nephew who loves his Wife and kindly told him to "Fuck Off!"
I was shocked but not surprised at all about this. I'm sure the Spanish side of our family as me and my cousins Dads came from Spain feel the same way.
I could only imagine what they have said when we are not looking or listening.
Racism exists everywhere even in our own families and groups. Its sad but I hope you went and put that person in his place for saying a statement that is so ignorant.