When people get an idea into their heads about what a character should or shouldn't be (and even with mountains of evidence that proves their particular 'insights' to be false ones), they cannot stand a single thing that tarnishes the image they have loved on for so long.
It becomes a particular problem when fanon becomes canon.
"My Superman wouldn't kill. My Superman would make sure to save every single person. My Superman lives in a happy world."
These are all things I've seen as complaints against MOS. People assert them as the truth, and then when it's pointed out that really, no it's not the truth, they suddenly want to ignore those inconvenient bits of canon to continue to complain.
It's all about perception. Some people see Superman as the absolute 100% perfect being, who could never do a thing wrong. Other people see him as a pacifist or too gentle to kill.
MOS jolted some people from those sweet fantasies. It's hard to deal with your perceptions being ripped apart, while all the things you tend to ignore in canon are waved in your face for two and a half hours.
It's such a shame too, that fanon has ruined the film for so many people, because I think it's probably one of the better films that's come out over the past two years.
Brilliant
I can somewhat sympathize with those who do not like this take on the character. I prefered the Burton Batman films to Nolans, and I still do. Are Nolan's extremely grounded and realistic Batman films anywhere near what the comics are? I doubt it. BUT even though I may prefer the style and feel of Burton's Batman, that did not stop me from enjoying Nolan's Batman films for what they were: very well done crime thrillers that just happened to have Batman. Its hard to even describe them as a comic book or superhero movie, yet that didnt seem to stop people from like the movies.
I thought Batman Begins was terribly overrated, but the Dark Knight is the superb film everyone says it is, but of course with a few flaws that everyone tends to overlook (two face is tacked on at the end and then killed by Batman)
But Man of Steel has flaws too. Im a huge Man of Steel fan, and I admit that, but to me the postives from the film more then make up for those flaws. The problem is, when you can't get over "fanon" as your brilliantly call it, really minor issues tend to be magnified in your eyes. Was two-face being tacked on and killed by Batman a minor issue? In the grand scheme of the entire movie, yes, it was minor. Theres even people who, remarkably, are totally against the idea of Superman fighting so much in a movie. They'd rather him play the role of the protector, as in never throwing a punch like the Donner and Singer films.
The biggest and oddest complaint Ive seen is that there is no joy. Watching Superman save oil rig workers, kids on a bus, watching him fly for the first time, watching him being born, or returning to his mother still in the suit after the smallville fight isn't moments of joy? Johnathon Kent watching young Clark with the cape isnt joyful? No heart? Colonel Hardy saying "This man is not our enemy" after he walks out of the rubble to the tune of Hans Zimmer hair raising score isnt showing heart? His reaction to killing Zod? Perry White reaching out to comfort Jenny in the face of death isnt showing heart? "You can save them. You can save all of them." There wasnt heart in those words of Jor-El?
Man of Steel had joy, it had heart, it just came in ways different from the previous films. The Donner and Singer films showed heart through romance. Man of Steel does it differently and I feel people just werent looking in the right places, so it totally flew over their head.