He has a superhero name. It’s as stupid as every other superhero name. It’s not something you can comfortably call another person in casual conversation. Just try to have a normal-sounding talk with some of the guys in the Liberty Force. “So, hello, uh, Pile-Driver Man. And, how are you doing, Dynamic Woman?” You can’t. You honestly can’t. You need to have a superhero name, and so he has one, bestowed upon him by others when he lagged too long in coming up with one for himself. It still seems vainglorious to him.