We all know the story, two doting parents take their only son to a night out at the movies, only to be tragically gunned down in front of him. This moment forever changes the boy, leading him down the path that would culminate in him donning the cowl of The Batman and waging his one-man war against crime in Gotham City.
Part of what makes Batman resonate with readers is that his powers don't define him. Anyone could be Batman, given a seemingly bottomless bank account and a couple decades of intensive training (or even just an obsessive hard-on for justice and an alternative fashion sense). He can't leap tall buildings in a single bound, he isn't faster than a speeding bullet, but he's got a will more powerful than a locomotive.
Really, there isn't anything stopping someone from putting on hockey pads and a Halloween mask and calling themselves The Batman (except Christian Bale that one time). If they believe it, who's to tell them they're wrong? Batman helps inspire us to be the people we can be through drive and determination, the best of ourselves. He displays the height of human potential.
At his core, Batman is just that, a man adopting the visage of a bat, doing everything in his power to save his city from injustice, and so are these men.