- There is no harm

Yes, human beings should be allowed to use animals as objects of sports and entertainment, because people enjoy it, and there is little harm to the animals. An animal isn't hurt when it is taught to do a trick. There is no reason not to allow it, as long as people make sure that the animals are not hurt.

(There are some other cases, when people use dogs to create dog fights. And these cruel fights affect the animal mental and physical health, and this will make these dogs become even more dangerous to human. So you can't be sure that in all cases, the trained animals aren't hurt)

- Teaching method

Most people do not realize that they are using their pets as a form of entertainment at one time or another. When you play fetch with your dog, that is the same thing as teaching a dolphin to jump through a hoop.

(When you train your dog, you do it because you love your dog and you don't force to do anything for you. While training animals to do tricks for entertaining is another case. You are forcing the animals to do the things they don't want in order to make money. And that's why your comparison is irrelevant

- Animals are inferior to humans

In my opinion, animals are definitely inferior and less intelligent than humans. We eat animals, ride horses for recreation, make oxen plow the fields... So there is no reason they shouldn't be used as objects of sport and entertainment too.

(Many animals seem to be far more intelligent than humans nowadays, think about it... They are living creatures, and feel pain. They were meant not to be used as entertainment for our pleasure. Things like racing and fighting are inhumane and cruel.)

- Cultures

All cultures throughout history have used animals in the context of sport and entertainment, from Roman chariot racing up to present day hunting, racing, and circuses. There are two categories of activity that are acceptable: first, killing animals that are pests or that are going to be eaten; and secondly, using animals in enjoyable human sports in ways that do not involve cruelty.

(in cases such as dog fighting, bullfighting, hunting, animals are still injured. So, therefore, u cannot 100% sure that animals are not always injured )"