They didn't really explore those themes (of course they didn't--Snyder--), but Riddick makes a good point. Really, the terraforming was a means of ensuring the survival of the Kryptonian species. And Superman saved humans, and killed his own people, essentially committing genocide against the remaining Kryptonians and ensuring the end of Kryptonians forever. Unless, I guess, Superman decides to clone himself at some point, and use that as the starting point to repopulate the race of Kryptonians
In that sense, Zod could be one of the more sympathetic "villains" out there. Sure, he was a bit sadistic. But at the end of the day, he's just trying to survive. Anyone else would do the same in his position. All other villains are driven by power or wealth, or if you want to go a bit deeper, by some psychological disturbance (Joker being the most obvious example there, but it also applies to someone like
Luthor, Kingpin, Loki, Trump, etc.), usually arising from childhood.
