Did any of you lot actually read the article?
That really is precisely what the article links to suggests - or not - depending upon the reader's initial view. The slight elevated risk of cancer actually would simply bring the worker life expectancy to near population normal rates. Without sorting out nuclear-plant workers from the general population first and then comparing the Fukushima workers specifically against that subpopulation no effect would be detectable. Even using the subsampling would be problematic because the effect on the rate is "slight." The fact is that without a much larger population of exposed workers the measurable effect will be lost in statistical noise. Also, different types of radiation present different hazard levels. As long you don't ingest or inhale alpha emitters, alpha radiation is nearly harmless. The outer layers of the skin, which are basically a dead armor, will be sloughed off and no effects should actually enter the living part of the system. UV from sunlight is more hazardous.
The effectiveness of the evacuation is in fact unknown. The exposure of the population would be in general lower than that experienced by the workers at the plant. The given the size of the evacuated population, the statistics would very likely reveal what affect the exposure might have had, if they had remained in place. As it is, some people might have had their lives shortened by the exposure, but you would never be able to say which. Instead, we really do know how many died because of the evacuation and who those were. Personally, I'm not sure which is better.