In the marines and Green Berets, there's a saying that's passed into the popular culture: "Kill 'em all, and let God sort 'em out." According to the best information I could find, this dates to around 1210 CE, when Pope Innocent III took a hard line on heresy. At some point after a hundred thousand or so had been massacred, a bunch of "heretics" were captured, many of whom claimed not to be heretics (and who can blame them?). The papal legate basically said this in response, quite possibly in Latin, maybe in French. In either case, it probably sounds more badass in English.
Well, I guess it's one way to go.
For my part, I prefer "Allow them all to live, and let Santa Claus sort them out." After all, he knows who's naughty and who's nice, and he only has to wait until late December each year. And nobody gets hurt.
Everybody's got their judgmental imaginary friends, right?