the "good deed" is that the city is providing a service that would otherwise be unavailable to the people in the county. The city is paying the bulk of the funding, the training, and the equipment.
It's more like someone saying "I'm hungry and you have a warehouse full of food. I can just walk in and help myself to all I want. You've already paid for the food, so I can take what I want for free"
As a business owner, it is like all your customers finding out that you will give them a service even if they never pay for it. "Yeah, he sent me a bill and I never paid it. When I ordered again, he still sent me stuff so I think I'll just keep not paying." Then all your other customers hear about that and say "well why the heck am I paying? I bet he's going to raise the rates to pay for all these freeloaders anyway"
The decision to not fight the fire was never made by the firemen. The word comes from the dispatch office "This home is outside your area. Do not provide service" I can't say that the firemen would have been "fired" since they are volunteers after all, but what if one of them got hurt. Do you realize that they would have no insurance? Worker's comp would not pay because the house wasn't owned by a "customer"
What if 1 firefighter decided to put out the fire anyway or to help carry stuff out. Then the roof collapses. Now you have the entire crew in danger trying to get him out. They save him, but now he has horrible burn injuries. There is no insurance coverage so he is left with all the bills for medical treatment. He can't work, so now his family is in danger of being homeless. He is permanently scarred and disabled, living on government assistance. All because someone couldn't be bothered to pay a lousy $75 fee.