so you are saying the dog was used as an instrument of racial hatred. A tool of racism so to speak? That makes more sense.
The actual dog Romain Gary wrote about (and Gary admits he took some artistic liberties himself in telling the story of his and his wife's experiences, we should remember) was supposed to have been trained by a southern policeman--the father of that policeman, who was also a trainer, showed up to claim the dog, with his grandchildren in tow--he was a tall, handsome, charming man--Gary really let him have it with some pretty savage sarcasm.
Batka (the name of the dog in the book) probably would have been one of those dogs you see in the archival footage of civil rights protestors in Birmingham being harassed--the kind of police dog used to intimidate people, chase down suspects, etc. He was there for added muscle--no indication he was used for drug sniffing, tracking, etc. Faster than any man, extremely powerful and intimidating, and willing to do what he was told without question. Shock troops.
And he had clearly been conditioned to have a intensely hostile reaction to black people, specifically black men. He did not have the same reaction to very small children who happened to be black, who he even showed affection towards on several occasions. No mention of how he reacted to black women. He did not actually hurt any black people during the time Gary knew him, but he was certainly capable of it.
I know from my own experiences that a dog who is attacked by another dog of a specific breed (say a poodle), may often react badly to that type of dog in the future--that's prejudice, and it's a natural reaction, that might save the dog's life if he or she were living in a wild state. Jumping to conclusions based on past experiences may often lead to misjudgements of the other dog, but better to err on the side of caution if you believe your life could be at risk. None of that constitutes racism against poodles. And of course body coloration is meaningless to a dog. Wolves in the same pack may be several different colors. Basically, you could train a dog to have a fearful and/or hostile reaction to anything--you could make him be aggressive towards people wearing hats. This is particularly true of breeds like the German Shepherd Dog, who are especially trainable and open to suggestion.
It's important to remember that the real dog was retrained to like and obey black people within several weeks. Unfortunately, as Gary tells the story--well, read the book.
There was a movie in the early 70's called "The Doberman Gang", about Dobermans trained to rob banks. This idea was fun and interesting , but far from realistic. Dogs do not understand the concept of money. Sure, you can train a team of dogs to perform separate tasks, but a dog's mind isn't complex enough to understand the urgency or value of money.
I've yet to see that movie, so I can't comment--obviously a dog can't understand the value of money, but he could learn to associate it with obtaining praise and rewards from his people, and that might make him feel happy and reassured in its presence.