As a small child, Bruce Wayne witnessed a hoodlum murdering his parents. Outside the comic book universe, he might have grown up and become a lobbyist for handgun control, or he might have founded Adult Children of Gunned-Down Parents. Instead he became a twisted vigilante with a mask fetish.
Life is unpredictable.
Just as odd as the hero's canonical origin is the true story of how the character came to exist. He went home and invented the Batman. In Kane's first sketches, Batman wore a red union suit and bulky bat-wings. The public liked it. During the Golden Age of comics, from 1938 to 1954, there were 700-plus costumed characters.