[I don't know, I thought the movie got across that point pretty well. We saw the stunned reaction when Zod made his dramatic appearance, and we saw the reaction of the military and people like Hamilton when Superman stepped forward. Or the frightened and/or amazed reaction of people who were saved earlier by Clark (with some seeming to think he was some kind of religious savior). Not to mention the "oh shit" reaction of the priest..
That's mostly because Zod made a threat and already showed hostile intention. I'm talking about the theme or idea of humans being are weary of what they don't understand due to a lack of exposure. It would have added more dramatic legs to the introspective crisis Clark was facing or contextualized it in a different way, with him having to face some fear, paranoia or suspicion of him due to him having powers beyond mortal men. With that in place you could show Supes working to earn the trust of people instead of the usual Oh hey! cool! An alien!