We are so used to assuming that Superman = good that we forget that is a contingent and not a necessary correlation. It could be otherwise.
My husband told me about a short story he read in which the people discover this about G*d. They discover that there is a G*d but he is not good and essentially everyone is doomed to eternal misery. So they get busy putting everyone in suspended animation so that no one will ever die.
This is also why, in a world with Superman, any responsible government would be stockpiling and weaponizing kryptonite left and right.
