///Spoiler Alert///
Superman killing Zod was a direct rejection of the idea that killing is always avoidable.
In most cases for Superman, killing is avoidable. He wouldn’t be much of a hero if he went around punching bank robbers to death. Yeah, robbing banks is a crime, but you’re bulletproof, so just bend their guns into pretzels, haul the bad guys to the police station and call it a day. It’s a good moral context where restraint is appropriate.
Zod, in his case, was no bank robber. He was a superpowered genocidal maniac, bred to a specific purpose, and either unable or unwilling to change from that purpose. He was perfectly clear that his intention was to kill every human being on Earth, and rebuild Krypton on our ashes. Period. Full stop.
He was also a trained, expert combatant from an ancient starfaring civilization, with technical and tactical knowledge far in excess of a Kansas farm boy. Meaning, once Zod adjusted fully to his new powers, he’d be more than a match for Superman. He was clearly disoriented and confused by his new powers, but before long he’d be as strong as Superman, and infinitely more dangerous.
Superman (and his father) had tried to reason with him, and Zod was perfectly clear that he wasn’t interested in any solution that didn’t involve killing all humans. At the point when Superman kills Zod, Zod is trying to murder people, literally at random, specifically to make the point to Superman that he won’t ever stop until he’s killed us all. There was no ‘Kneel before Zod’ scene because Zod didn’t want our submission. He wanted our extermination.
That doesn’t leave a lot of options. Zod isn’t something that can be contained. Even Krypton failed at that. What chance would Earth have?
If your argument is ‘well, the writers should have set it up that Superman could have saved the day without getting his hands dirty’, then that’s fine. Given the scenario presented, however, that wasn’t an option, and Superman was entirely justified in his actions. Further restraint at that point would have seen that family incinerated, and likely doom the world to extinction. If that doesn’t justify killing, then nothing does.
I agree there’s a place for this kind of “debate Superman killing Zod” and you do a good job. And as you suggest at the end, all the writers had to do was make the phantom zone projector available and the legend as we know it would live on. Superman has faced *much* worse situations than the one presented in this movie and kept his obligation to respect all life.
But this is exactly my point - all the interesting what-if’ing aside: Goyer and Nolan don’t like that legend. They like their Superman to be a killer if he needs to be. Why? What purpose does it serve? Other than to reflect the nihilistic “amoral when we ‘have’ to be” society we’re becoming.
I said it before in this thread, the small and silver screens positively hemorrhage characters that fit that bill. Superman is Superman because he can always make the right choice and maintain his aforementioned obligation. leave me my Superman. Must we corrupt even him? Who’s agenda does that serve, anyway?