When I was in Vietnam we had dogs around. They didn’t act any differently around dark green or light green Marines, but when we took one for a ride with us in a truck through a village they barked at Vietnamese people. Their dogs barked at us. The pack.
I currently have a rotti/shep mix. He thinks it’s his job to protect us. He has already saved our lives from the mail man and an Amazon man today. Race doesn’t matter. He barks at everyone who comes around. Once I let someone in I can tell him to stop it. He is quicker to not think he needs to protect us when the visitor is female, race doesn’t seem to matter. But then we have people of all races for friends and he probably doesn’t pick up different vibes from us for people of different races.
I am not an animal behavior expert so I can’t tell you why dogs respond differently to different people, but a dog’s pack (family) can have multi-racial humans just fine. I do know that.