Just because nobody cared to study the problem and actually attribute the deaths that were happening doesn't mean nobody died.
But a million nukebros on the Internet will tell you nuclear power is the world's safest power source. (wrong)
Only 31 people died from Chernobyl! (very wrong)
Nobody died from radiation at Fukushima! (also wrong, trivially debunked, and still repeated to this day for whatever reason)