@Miranox only partly, yeah, we have a "fear of the unknown", it's a survival instinct - but if we fear people looking other than ourselves is heavily influenced by our education and environment
if a child grow up with people of different looks, cultures etc and everyone is treated as precious (you can be/do what you are/want as long as you don't harm another) then this child will to 99% grow up to be very unbiased even if it encounters an "alien" it will most likely not think "bad cause different from me"
but you're right that every society cherishes itself the most and bad people will quite often pictured as foreigners or with other as negative considered attributes (like how often is the bad noble a fatty one...)
and this "cursed bloodline" sounds to me like the typical case of nobles secretly siring children with common people, so here and there the genes come through and peng, magic activated