Pretty sure people are talking about "Golbez" (Durante), not Contramemoria-era Golbez. They're two different people.
Me, personally?
First I'd try to find out what and then why, so as to prevent it from happening again if at all possible. Going back to the old status quo would be completely meaningless if the same phenomenon just broke it again! ... but I would also recognize that going back to the old status quo is impossible no matter what you do, and so try to find a way forward.
Certainly not engage in a millennia-long genocidal campaign weakly excused by failings I engender in the new humanity! I mean, if you focus only on the bad - judge people at their worst - well, you've kind of already made up your mind, haven't you? Conversely if you look back on the past with rose-tinted goggles you'll never see, much less appreciate, the endless possibilities of the future...
Has that not been like, the core overarching message of the story since A Realm Reborn? Did I miss something somewhere?