28 Years Later

In order to believe in isolationism, you must hide the truth from yourself and others. You need to construct a ficticious reality that's simpler, easier, and more rewarding than the real world. Then, you need to sell it.

In the case of 28 Years Later, the characters don't have much of a choice in the matter. The British Isles are quarantined from the rest of the world, and their village is quarantined from the rest of the British Isles. There are no means of rejoining broader society, so their community is forced to embrace the dishonesties of isolationism as a means of survival. They must lie to themselves, their families, and their peers in order to extract meaning from their daily lives. They need to exist in a fabricated reality as a means of being somewhat proud of their "accomplishments" and their community.

In short, when you're in isolation, you have to pretend that things are better than they are. There's nothing out there. It's chaos. It's zombies hanging dong. That fire over there? There's something sinister about it. If there is a doctor somewhere out there in the wilderness, they've gone insane with bloodlust.

In order to sustain itself, the isolated community in 28 Years Later pretends everything is 20% stronger, everyone is 20% healthier, and daily tasks are 20% more courageous or important or whatever. Like any society of a similar ilk, these self-deceptions are useful in the beginning, and they remain in tact for some time, maybe one generation, before everything comes apart at the seams (because obviously the whole point is that you can't really live in isolation, you have to try and expand, you know, grow, evolve, whatever).

Eventually, the first generation of isolationists are tasked with convincing their children that the way society functions is totallyyy fineee. They've resigned themselves to this state of being by tricking themselves into believing that their world is okay just the way it is. They just need to convince the younger generation (the second generation after the rage virus) to succumb to their collective psychosis. This, of course, is an impossible task in the long-term.

Once the youth start catching onto the lies about how "exceptional it is here compared to the outside world" and how "there's nothing else anywhere except for pain", the community will be forced to reckon with the buried truths of their reality. They realize that the people going out to fight aren't as heroic as they're being portrayed (there are plenty of analogies to be made to the domestic perceptions of militaries (namely those of the American/British variety), but alas). Regardless of the mode, motive, or malliciousness of mass-deception, the truth will unravel in a matter of time. The youth will always be prone to challenging the status quo and unearthing the issues that plague their society, and 28 Years Later's study on isolationism emphasizes this unavoidable dilemna.

We can't always shelter ourselves and others from reality (cough Brexit) (cough Trump-era isolationism) (cough sakoku) (cough etc.). Society needs to evolve and embrace change to have any chance at survival. This movie is about a lot of things that I didn't mention (including death, othering, growing up, and masculinity), but its the politically/culturally relevant examination of an isolated community that jumps off the screen as an ominous forecast for those who dare romanticize nationalism or isolationism.