We got a Black Labrador when he was five years old, and he's been a really wonderful dog in the years we've had him. Normally he barks to let us know when people have arrived at our front door, but calms down quickly when we let them in and is very friendly to our guests.
A week ago, my Asian friend, whom my dog had never met, came by to pick something up. As soon as my dog saw him in the window, he went absolutely ballistic in a way that I had never seen before. He would not stop barking at my friend when he came in, but fortunately he did not try to bite. My friend didn't think anything of it and tried petting him (my dog tried to avoid it), but I was absolutely mortified that he was behaving so angrily towards my friend. It was a short visit and my dog was on edge for a while afterwards.
I had kind of forgotten the incident until I was walking my dog and we passed an Asian man I didn't know. My dog also went crazy over him and I had to drag him away. My area has very few Asians living in it, so this is a rarity. I wondered if my dog was reacting to their appearance, especially given that in both cases it's very unlikely he smelled anything.
Since I don't know anything about my dog's early life, I'm going to give him the benefit of the doubt and assume that he's not "racist", but rather has an understandable reason for this reaction, such as a very negative experience with someone who is Asian. He hadn't really been exposed to them since living with me, so there was no chance to get acclimated.
What can I do to help my dog overcome this strong reaction to Asian men? Would having my friend spend time with him (or just be present at my house more often) be enough?