Re: dogs. I’m aware that an alarmingly large number of black people in the USA have been the victims of dog attacks (not in the UK as far as I know though). I have also heard that dogs can be trained to hate black people… but I don’t believe that. Dogs recognise certain individuals and can be trained to react to certain stimuli. But visual appearances? Less so.
I recall a story of a four-limb deficient Thalidomide victim. Her dog was trained to go off and find a cop when she was in trouble. Supposedly the dog was trained to spot a police uniform. When the owner got in trouble, the dog was released as planned but came back with a soldier. People thought the dog’s uniform recognition was incorrect but it’s rather more likely that the dog thought “I’ve got to find an adult male who’s walking around like he’s got a stick up his arse”.
If even a smart dog like that one doesn’t recognise a uniform, which is made of distinctive fibres, it won’t recognise the colour of a face either. They can, however, be trained to react to an ‘attack word’. Or if their owner genuinely does hate black people, his body might tense when he sees one. The dog would be aware of the sign of stress and perceive a threat to the owner.