It is a compelling story.
As for why the public was ignorant to the danger; radiation was only discovered in 1895 (x-rays). First injuries the following year from x-ray exposure. First death in 1904.
I am no expert, so I can only speculate. Thinking that pre-internet, information moved slower and scientific information slower still. The radium they were using was "different" and really trendy. Even a handful of deaths wouldn't repel the masses. It was only 12 years after the x-ray deaths.
If I can be cynical for a moment, this is a cycle that replays far too often. Some industry uses a product that is more or less known to be dangerous and it is only with years or decades of evidence, public outrage, and government intervention does that industry change its ways. Not always is it malicious or intentional, but this kind of thing does seem to happen a lot.