Conditioned preferences in traits, behavior..it's all relative. Every society has its own customs and taboo. The most common subconscious attraction has to do with fertility: on a subconscious level, most humans desire those who show they are the most physically capable of reproducing. Obviously, most of them don't realize it; they don't just go up to someone and say "You look like you could propagate."
Because we have to chase him. Because he's the hero Gotham deserves, but not the one it needs right now. So we'll hunt him. Because he can take it. Because he's not our hero. He's a silent guardian, a watchful protector. A dark knight.