... and the rest, outside of the "vast majority" (a vastly
overused favorite term on the internet) was Kal's fault.
It's like if a mad gunman sprays a schoolyard and kills a dozen kids, and an armed citizen returns fire, but his stray rounds kill 6 kids too.
It's not okay.
Perhaps you should rewatch the final 3rd of the movie. All the buildings Superman and Zod crashed into were empty; except the last one where Zod attempted to kill that family.
I find it disingenuous to blame Superman for the casualties in the film. In MOS, Superman had no control of the situation. He's fighting people just as powerful as he is. His net advantage against Zod is 0. He was at a disadvantage against Faora and Nam-Ek in the Smallville fight since it was 2 against 1.