There was simply a false assumption about how dangerous radiation was. Some of this still persists to this day.
A nuclear reactor that had the same radiation as a coal plant would not be legal? How does this make any sense at all?
The Safety standards were actually put at to high a level to early, specially given how instantly save nuclear was.
Consider this, how safe were coal plants? Would nuclear instead of coal have saved 100000s of lives since then? Yes of course nuclear would have, even if you had an accident once in a while.
The problem is that there was 0 tolerance for nuclear accident, because of populist nonsense, but if coal plant and supply chain killed 5 people here 10 people and 1000s of people get sick, nobody cares.
So the reality is, that nuclear went uneconomical because nuclear and existing power production (mostly coal, later gas) were no treated the same in terms of their safety requirements.
> When you are building a power plant which has the capability of making a significant portion of your country permanently incompatible with human life
That's not actually what happens. 3 Mile Island or Fukushima didn't even remotely come close to what you describe. And even for Chernobyl this is questionable statement. And Chernobyl was a type of reactor not built in the West, so in the West something that bad simply can't happen with PWRs.