I've never been afraid of thunderstorms.
As children my siblings and I would sit at the window and watch violent electrical storms tear the sky apart with blinding spidery fingers of light and covered our ears to dampen the inevitable deafening thunderclaps that would follow.
When we could hear again we'd give measured and considered scores out of 10 for each display before shrieking with delight at the next one.
I would imagine what our neighbourhood would look like if enough rain fell to turn the streets into canals and allow us to travel about in dinghies, kayaks and speed boats instead of cars and of course we would act this scenario out for whole days at a time.
One day we were running around playing 'what we would do if everything was flooded' and some well-meaning adult decided to give us a firm but kind talk on the realities of flooding - the property destroyed, lives lost, lives ruined - and ask us if maybe we weren't being a bit insensitive?
We stared at them, stared at each other and ran off to keep playing but the fun had been taken out of the game for that day.
The thing is, now that I'm older I know that having water up to your ceiling would not be great for the neighbourhood but we weren't earnestly suggesting it should happen, random Reality McBuzzkillington!
Why not point out to me that the carpet is not really lava and that if a volcano really did erupt, those of us not killed by the superheated cloud of poisonous gases would probably be asphyxiated by the falling ash?
Why not run up to the kids playing sword fights and explain to them that being stabbed with a sword would really not be all that great? Or that the person you say can't stab you any more because their arm has 'fallen off' probably has leprosy and how gross real leprosy would be?
Kids use play to interact with each other, to learn to understand the world and to develop the parts of their brains that will eventually help them to imagine the lives of other people in an empathetic and responsible fashion.
Don't tell them it isn't cool to pretend you've just disemboweled somebody; they're not desensitised to disembowelling, they're just mucking around.
There are some exceptions to this thinking.
For instance, I can see how people in a community who actually have regular access to guns and who treat these weapons with caution and respect would discourage letting kids 'shoot' each other just in case they ever got hold of a real gun and didn't realise that when they shot their friends with that gun they wouldn't be getting up to swap places.
But the kids that pretend that their towns are flooded aren't going to go bust the dam for funsies.
The kids who pretend to chop off people's heads aren't going to start a skull collection.
The kids who pretend to be monsters who are eating you aren't going to become cannibals.
Just let the little nutters play, age brings context but youth is for imagination.