This Batman isn't motivated by some complex, perpetual quest to avenge the death of his parents. He's also certainly not some maniac that wants to rule through fear, watch the world burn, or even make himself Gotham's reckoning.
He just wants cookies, and beating up criminals seems to be the most thrilling way to get them.
For instance, he just got a tip that a mugger a few blocks down is armed with some Pepperidge Farm Milanos. -- He's SO there.