I'm not complaining because it's not spelled out for me, I'm complaining because that would have been a really interesting avenue to explore, and I'm sad that they didn't. The movie they chose to make is not the movie I ended up wanting to see, is I guess what I'm saying. It was kind of cool in parts, but could have gone in some different directions and been a lot more interesting (to me, at least). Also, I can't really believe that a Pulitzer-winning article was a simple case of sour grapes: "fine, he's gone, we didn't need him anyway." If it was worthy of Pulitzer I have to assume it had some ideas that I would want to hear.
Similar themes were broached in Kingdom Come, and much more ably to my thinking: Superman leaves, comes back, and people are not sure they want him back. The presence of a superhero to solve all our problems for us makes the concept of human achievement a moot point. They go so far as to launch nukes at Superman (and hundreds of other supers) as a last-ditch attempt to retain control of their own destinies, rather than surrender the world to super-human caretakers. In the movie, on the other hand, they just stand up and applaud and say "Yay, now Superman's here to solve our problems again."
I think that, more than anything, is the most damning commentary on the human race--Kal-El chose to make Clark passive instead of active, the kind of person who lets other people fix things, and for the most part that is what humanity does when Superman is around. I admit that Lois and her fiance go to great lengths to save Superman's life, and the movie makes a point about the fact that they're doing it because Superman has inspired them with his example, but I think you could take that same situation and apply to any other superhero. Someone could be inspired to save Batman's life, too. There is nothing in Superman's actions or words (at the least in the movie) that encourages other people to stand up for themselves--he doesn't teach them to fish, so to speak, he just does all the fishing and gets lucky when Lois pays enough attention to pick it up on her own. Regardless of what you say about the relative attitudes of Superman and Batman (one sees the world as something with potential, and the other sees the world as something that needs to be protected), their actual actions are the same in the end.
(Actually, I think you could make a really good case about how Batman sees and directly inspires more potential than Superman ever does, because Batman actively recruits helpers. In Batman Begins, Bruce starts a crusade against evil and gets a whole group of helpers on his "team": Alfred, the girl, Morgan Freeman, and Commissioner Gordon--sorry, I forget some of the names. He sees potential in them, and gives them the tools and the opportunity and the trust to realize that potential and make the world a better place. Batman is practically defined by that quality, constantly surrounding himself with Robins and Batgirls and Oracles and all kinds of allies. Superman is either a lone wolf or a member of the JLA, which is a team of pre-existing superheroes who unite by necessity rather than because Superman inspired them to greatness. Now I realize that this isn't a very fair comparison, because Superman spends most of his time fighting cosmic bad guys in a completely different league of danger, and Jimmy or Lois wouldn't be much help at all. Still, though, it's interesting to think about.)