Why didn't Batman kill the clown?

Batman is the messenger of justice. In order to eradicate evil, he studied fighting skills all over the world, gave up the comfortable life, and chose to demand himself with cruel training and unimaginable self-discipline, thus giving himself the ultimate physical level and thinking ability of mankind.

In order to create an opponent for Batman, the clown came into being. Batman is the guardian of justice, then the clown is the maker of evil and trouble. The clown's behavior is beyond normal people's understanding. He kidnapped others and killed people, not to get something for himself, but simply to kill people, or to test his ideas. He completely liberated himself and completely abandoned the constraints that a person should have. Perhaps this is why clowns have been regarded as the most attractive villains for so many years. In the face of Batman's pursuit, if he feels that he can't escape or there is no need to escape, he will choose to surrender and be brought back by Batman. He knew Batman wouldn't kill him if he didn't kill people. When he is put in a madhouse, and when he wants to come out, he will wait for the next chance to commit a crime!

Batman doesn't kill clowns for two reasons. The first reason is that he is a messenger of justice. He only catches criminals, not kills them. This is Batman's setting and his charm as a superhero. The second reason should be that Batman feels that the clown is responsible for falling into the chemical reagent barrel from an ordinary person in the process of catching criminals. He wanted to influence the clown, so he didn't kill him.

People who enjoy doing evil like clowns are actually beyond the scope of ordinary people. If a superhero is here to protect the world, a clown is here to destroy it, an antisocial character and a madman.