Well there is a clear evolutionary advantage to being wary of ‘difference’ and you can see that behaviour in nearly every species. Yes, even fluffy puppy dogs.
Human society is the one exception. We have beaten mother nature in the natural world (hunger, warmth and shelter) and now we are focussing on the primordial mother nature within us. Where we cant directly fix a physical or genetic weakness, we reprogramme ourselves (via society) to normalise and accept differences amongst us.
Attitudes to Rudolph show how much we have changed in recent years.