They're just looking at death rates, not the reduced economic activity due to restrictions in usable land, and the transition costs for moving. They also looked at, say, the mortality rate for the thyroid cancer and count the 2-8% death rate only The other 92% suffered nothing I guess. . . /s

But i'll grant them that coal seems way way worse. Though basing on 2007 study is a time before the IED kicked in and a lot of LCPD plants were running limited hours instead of scrubbers - modern coal has to be cleaner by the directive - unfortunately the article is paywalled so hard to tell what their sample was based on time-wise and tech-wise.

Hydro estimate is interesting because it shows the impact of the one off major catastrophic event.