There may be many reasons why dogs like fakes. One possible reason is that the dog may like fake sounds or movements. For example, your dog may enjoy hearing you make a fake "hush!" sound or seeing you imitate a fake throwing thing. This may get the dog excited and want to join in. Another possible reason is that your dog may enjoy interacting with you. Dogs are social animals and they enjoy interacting with humans or other animals. Fake sounds or movements may attract your dog's attention and make them want to play with you. Additionally, dogs may enjoy fake sounds or actions because they may lead to rewards. For example, if you make a fake "ho!" sound and your dog responds to the sound, you might give him a reward, such as food or a toy.
This may make the dog think that the fake sounds or actions are meaningful and continue to react that way. Overall, dogs may enjoy fake sounds or movements because they bring excitement, interaction, and reward. This is a way for dogs to interact with humans and a way for dogs to entertain themselves.