Did Supes REALLY needed to get revenge on Rocky?

I had your reaction initially and thought it was a silly act of revenge from a superhero that explicitly advertises very lofty ideals and implores humanity to live by them. I figured this scene was tossed in for a somewhat cheap crowd pleasing ending, which I do think was effective even if out of character for Superman. However, I've since softened that stance and agree with others that Superman is pretty much half human. He's physically a super being from Krypton and culturally human (save his Kryptonian education), which means he's vulnerable to the same instincts as most everyone else, including the satisfaction that comes with getting even. It's also possible to interpret this as a combined act of revenge and altruism. In whittling Rocky down to size, he probably gave much relief to the diner owner and staff, as well as other regular customers who were weary of having a bully around who might go rogue at the slightest perceived insult.

of course he did he had always been Superman, humans his whole life appeared as weak and fragile like paper this wasn't a superman from some comics where he grew up and gained his powers later in life he was always super always invincible his only known weakness being Kryptonite he had felt an anger unlike anything maybe when he saw his blood he saw the true price he had paid and regretted his choice for the first time. for the first time since the death of his father felt helpless felt pathetic and weak he wanted his powers back some of those emotions he had never felt before when was A Superman so of course he wanted to comeback as Superman and make Rocky feel some of those things he made him feel for the first time

Was he getting revenge? Maybe.

I always thought it was great that the showed that it's worth it to stand up to bullies, if you can.