Wow... I love it. I love grappling with these issues honestly. I love the fairy tale aspect of super hero stories. But I love taking the responsibilities, pressures and conundrums Superman is forced to reckon with in a way that is serious and asks questions of what ramifications could arise from his mere existence. The morality of Superman, both intellectually, what's been established through creators and editorial fiat over decades is actually NOT some simplistic child like moral view that actually gets more obtuse the more you try to justify it in light of the character's actual history.
Look... I grew as a child in Reagan's America. We had in the country a an overweening pride in our strength militarily and our own moral righteousness. So you start asking, as a child with all the innocence and ignorance that a child has, why if we are so great and good that there are places in the world with such terrible leadership allowing or enacting on it's populations so much suffering. Why don't we just send our forces to kick ass, free people and set the world to right? (Any of you coming of age during this new century... Any of this sound familiar?)
As a sober minded adult who can take a long view, with some perspective and a little gained wisdom, that view seems so very childish and naïve to me now. It's based off of a limited understanding of human nature and history. One thing that changed my thoughts on this was exploring the Superman mythos.
What better stand in for the nation of the U.S. than Superman, right? And what I learned was that Superman does allow a lot of horrible things to happen not because he is immoral or ethically lacking, but because he IS moral and the responsibility on his shoulders means he cannot approach everything as if it were a simple case of punching out a bad guy or giving an inspirational and high minded speech appealing to our better angels. From setting himself up a as ultimate arbiter, to stunting the drive to excel in mankind to simply not seeing unintended consequences and beyond, Superman has a lot on his plate that he has to balance in trying to do the right thing (which, actually if we are grappling with morals in our lives we all are doing though on a scale that is far smaller than Superman's of course) as he sees it. It in fact, despite what others would prefer to think, SIMPLE, or SIMPLEMINDED. For all the smiles and good humor, if you truly are taking the character seriously, then he also MUST have an inner life which understands and accepts his own limitations on his influence on the planet and which indeed must be saddened at the terrible things he has to allow for the sake of issues greater to the whole of humanity than even individual lives often. This I like to think, spurs him on to be better and better at trying to thread the moral needles that are before him, that once he became an adult he's put great thought into.
Now, that is of course the ideal from the eternally in his thirties Superman of the printed page. For an adaptation to film the process of how such a character and his views come about has to be illustrated through a limited amount of a film's runtime, and the need for drama and conflict, better rounding of characters in general, all shape how he is going to come across on screen, and I am very happy that what we are seeing, since MOS really in my opinion, is a good grip on reckoning with the character as person with a real inner life and struggles, and the prequel comics point to BvS continuing this.