People want someone or something to blame. I think the reason is that certain groups think everything can be controlled. It’s too much of a challenge to their world view to have a large scale desaster not be attributed to someone’s fault. This causes them to dig in more with conspiracies. It’s easier to accept wild theories than change their world view.

It seems to typically be people who don’t have critical thinking skills. Those who can’t see past the superficial. A story that, on the surface, matches something that is true, then gives a speculative leap to something that isn’t, is hard for them to disregard. If A is true, and C happens sometimes with A, then A causes C. Without the ability to realize, B was skipped. Or to say it in a different way, its hard for some to realize correlation is not causation. So, conspiracies are born.

Ex: The ice is melting in Antarctica. Scientists are there all the time, drilling holes to get samples. If you drill a hole in an ice cube, more air gets to it and it melts faster. Therefore its the so called scientists that are causing the icecaps to melt. Maybe they are even putting heaters in it to speed it up just so they can say they were right. We need to stop these scientists before they kill us all. And so on.

(Old satirical article about what a good weapon wildfires can be)

Every disaster turns into conspiracy theories, especially when people believe that governments have weather control and earthquake machines.