None of that happened here. The zoning administration is an executive agency, not a court.
A sure sign that the fine was "imposed" in order to be waived is that it would cost the municipality more than a few hundred dollars to collect a few hundred dollars.
Anybody can send anybody else a letter saying "You need to talk with me." If you add to your letter "You owe me $300," then there's some chance that the person will talk with you. Better yet, maybe they'll get a lawyer, and you'll save some time because you can talk with the lawyer instead of with the scofflaw, a real plus if what you want to talk about is complying with the laws.
And, um, what nationwide backlash? Except for the God Squad, Americans here are generally accepting or supportive of the zoning adminsitrators.
Off the netz? Nobody's even heard of this. It's a local zoning beef, for Christ's sake. (Wanna bet whether 1 out of 10 Californians could place San Juan Capistrano on a map? How about New Yorkers? Texans? Nobody cares, dude.)
But I fully agree with you that if these people finally do comply with the law, then they will have no further bother from those whose job it is to administer and enforce the law.
And so we see yet again, the subtitle of this thread is a lie. Home Bibles studies are legal in the United States.