to be honest, cinge, this is one of those cases where they are right
i'm not a superman fan, never was. But i know of him. And i have to admit, that of all the many superheroes around who have the "never kill, always find another way" policy, superman is the one with the most reasons to follow such phylosophy
why ? because while ppl like spiderman, or batman or random_superhero_013 do this for a pure sense of self morality, Superman does it more because he's scare of himself. He knows that the moment he start to enter the gray area, he risks to take choices his superpowers can't allow him to take for the sake of the planet
he's scared that if he doesnt keep this strict limit to his actions, even if it means following the hard path while trying to find a solution to a problem, he would, one day, start to see as acceptable more shady actions. Of course it would still be for the good of the many, but he's scared that once he cross that line he will have a hard time finding another limit
because the only limit to Superman is Superman himself. Because no one could stop him if he wanted to tore appart the entire DC universe singlehandely
for this reason the fans are right. They took the single, more important part of the character and toss it away. It was like doing Spiderman without uncle Ben's death, or Wolverine being a sane goody guy, or doing a WWZ movie with Brad Pitt
sometimes, nerds are right to complain about differences