It is a biological standard in animals to base attraction on their parents and siblings. You will see this in any species with parental care. As you mature, your idea of the perfect partner stems from the evolutionary desire to create more like yourself. This is neurology, and is why people are attracted to others with the same demographics. It is normal for people to be attracted to their own kind, be that their religion, political stance, race, hair colour, activity levels, body shape, etc. It has nothing to do with racism.