You kind of answered your own question there. The film ends in such a quick and light-hearted way that it completely handwaves away the thousands upon thousands of deaths of innocents. Superman certainly shows no remorse over it. Instead, he just goes to work at the Daily Planet two days later where apparently everything's gone back to normal. Not a single newspaper headline. Nothing.
The film refuses to acknowledge it and that is such a huge, glaring issue that it goes well beyond just being a nitpick. There's a reason so many critics harp on the collateral damage in this film.
Do people honestly think there wasn't any casualites in the Avengers? But then again the Marvel films are all rainbows and butterflies, but hey it works.
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The price of fame is high and the Thing cant pay the way.
No argument here. He probably cauced many deaths directly himself, but didn`t have the luxury of playing it safe being inexperienced and all. Can`t make an omelet (or save the planet) without breaking a few eggs.
Then I guess we can say Superman isn't all of those Avengers combined, then, like some fans think he is(But against the Kryptonian invasion, you'd have to say Captain America, Black Widow and Hawkeye would have been non-factors. )But they also created struggles for him in MOS because of the 'Krypton atmosphere' thing around Zod's ship and World Engine, making him weaker and even powerless at times. It's something that would have only affected him, and not more of the other powerful Avengers like Thor & Hulk, had they been there. But that's just basic storytelling in both movies and comics - shaping the story where the heroes must overcome their weaknesses to win.
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"I'm not smart so much as I am not dumb." - Harlan Ellison
And IMO you would have to be kind of crazy to stay in the top floors of any of the buildings they crashed into considering their proximity to the huge gravity machine. I think it's highly possible everyone in the surrounding buildings either got evacuated or moved to the lower levels or basement(which is probably what would immediately happen in real life) But the gravity machine no doubt dealt out a lot of death.