Interesting thoughts on Zod's motivations, Virginia. I'm not sure it's where they were going with it (though I'm not entirely sure), but I like it as a retcon if nothing else.
Zod did threaten to kill all the humans, but that may have been bluster in the heat of the moment; he never got a chance to calm down. Of course, he would have killed many, many more people before calming down, so it's not like killing *everyone* was necessary for him to need to be stopped.
Also, Lynn has expressed my thoughts on Superman's reaction to killing Zod better than I could!
