What life is like in a state where firefighters are paid voluntarily

OK, but when you're considering whether and how to fight a fire in a burning building there's no court to make the decision for you; and even afterwards, all the expert witnesses are going to be firefighters talking about the particular risks presented by the particular structure.

If the insurance policy draws a distinction between whether or not lives at risk when a non-subscriber's call is answered, then the insurance company may have a case as you describe. But your comment seems to assume this is the norm, whereas the questionnaires I've looked at don't make that distinction.

Remember such insurance policies (issued to a FD) are upon life and limb, rather than on department revenue stability. An insurance company would challenge a payout if they felt the fire department (perhaps because of bad training or staffing policy) foolishly ordered a crew into an impossibly dangerous situation resulting in injury or death, even if the property owner was a paying subscriber. In reality, fire crews sometimes have to let a property burn and just try to stop the fire spreading, because the presence of chemicals or an unsafe building structure makes it too risky to enter.

The legal framework in this case would be a conversation along the lines:

FF: "Hello there, seems your house is a bit on fire sir."

HO: "Indeed, it would appear so. Would you be a good sport and point your enormous hose into my burning pile of rubble for a while, my dear lad?"

FF: "Of course, no problem. I do, however, see that you didn't pay into our 'unfortunate happenstance insurance', which means you'll have to pay our regular fees. That'll be a fantastilllion dollars and the blood of your firstborn please."

HO: "Here you go."

I grew up in Germany, which is without a doubt the most unhelpful and mean-spirited country in the whole world, and even they would not hesitate to help someone in need. The whole point of the "Good Samaritan" thing is that you don't do it for something in exchange, by the way. But in this case that doesn't even apply. The fire department would of course get something in exchange if they billed for their time and materials.

It should not matter how "evil" the family with the burning house is. It's simply morally wrong to not help them. This whole procedure highlights how deeply immoral some parts of society still are, especially in cases like this where it is apparently still seen as acceptable behavior.

By the way, not even in the dark ages, when there was no such thing as a professional fire brigade, ordinary people performed those duties without question for any member of the community. And those were the days when women were cattle and the church owned everything, mind you. But even they knew how absurd it was to only help some people in emergencies while leaving others with a self-righteous lie such as "there is nothing I can do, you deserve this".