The historical data on deaths per TW of power produced via different methods is readily available.
All Hansen et al have done is forecast ahead and combine the two sets of data to make the conclusions they have. Considering how pro-climate change Hansen is, and his activities which have upset the US Government over the years, I don’t think you can accuse him of pushing the US governments agenda to heavily.
Fundamentally, people are scared of nuclear power, and the long term issues of waste management. Mostly because they don’t understand, and the press likes to cause panic.
A cleaner nuclear method in the form of Thorium reactors would help alleviate a lot of the future waste issues, it still needs research conducting to make commercial and environmental sense, but the technology isn’t that far off compared to that of fusion power, and could act as a stop gap until fusion power is viable.