I think it's more that people who study the past ascribe violence (such as revolutions) to people going hungry, and they also associate hunger with short term (on the scale of a few years) climate.

Then on top of that, the largest volcanic eruptions (e.g. Tambora [1]) are known to impact the global climate in ways that are measurable, and indeed even observable to the layperson, over the scale of a few years.

It seems like it might be a legitimate line of scientific inquiry.

[1] https://en.wikipedia.org/wiki/1815_eruption_of_Mount_Tambora

People who make outlandish claims make it into peer review and then into news papers and get funding.

People who doing boring true but important things can have a harder time.

(Upvoting stories like this means we are part of the problem, but not sure of a solution)