wingedbeast

I want to be clear. There are some times when purity can be something good. You'll want to look for pure water. If you've found a stash of stored supplies, you'll want to know if the packages are still pure sugar or pure salt. Even a vat of pure feces has the benefit of knowing that it isn't tainted with some kind of herbicide and can be useful in fertilizing crops.

The moment someone starts applying that word to people is a moment you should start to fear.

There's an oft-recurring fantasy that plays out in the human mind, both on the individual level and on the societal level. You've had this fantasy, too. It's almost impossible not to. It's also nigh-impossible not to mistake this fantasy for an ideal reality. "This civilization would be great, if only everybody were..."

You should recognize that as the "nice" way of saying it. The "mean" way of conveying the exact same information is "This civilization would be great, if only we got rid of all the..."

Finish either sentence however you like and you will be wrong. Either you'll be wrong automatically or you'll be right tautologically, but wrong practically.

In pre-apocalyptic, but very nearly apocalyptic itself, history we had the example of people finishing the first sentence with "able-bodies, pure-blooded Germans". On the off-chance that records of this bit of pre-apocalyptic history haven't survived, this thinking resulted in what we call the Holocaust, a mass-murder of eleven point five million human beings. Six million were religiously and/or ethnically Jewish and the rest were made up of the Romani (called Gypsies), the mentally disabled, the homosexual, and any number of people who never thought they'd be one of the people they were trying, so hard, to get rid of.

Assuming those lessons are made obvious enough, you'll still have to contend with the desire for ideological purity. In pre-apocalyptic America, we have a vocal and influential minority that believes that America needs to be truly Christian.

In either case, the problems only start with inbreeding and move on from there. Biologically and intellectually, inbreeding means that internal defects become more powerful and infections that cause obvious harm can more readily spread.

That alone would be enough reason if not for the question of who is pure enough? How far back does one's ancestry go? How far orthodox does one's thinking run? Who is the True (insert ethnicity)? Who is the true (insert religious identification)? How well can you trust people who have their own power to protect to make that decision?

Again, you will have this fantasy and you might even mistake it for ideal reality. If you have no sympathies for those who think that society will be improved with ethnic purity, you'll certainly meet up with them enough to imagine it improved by being ideologically pure by rejecting those who seek ethnic purity. And, depending on the various faiths of survivors, you may even come to that paradoxical view that society will be improved by being ideologically pure by rejecting those who seek ideological purity.

Yes, that makes managing a society of diverse ideologies, including some that seek the exclusion of others, will be difficult. There will be limits to the amount of control you can maintain. But, some efforts of control will only doom you in the long run. Sometimes, you just have to accept the difficulty.