Homemade stills, especially during Prohibition and the World Wars, tend to be made from items that were not meant to be use for that purpose and chemicals from these leached into the moonshine. Also, some makers/seller would cut the shine with other things that then caused illness, paralysis, and even death. There was a famous side effect of one with "jake" (Jamcian ginger extract) that caused a distinct leg twitch called oddly enough.....Jake leg. ;) but only batches made after 1930. At that time the industry added a chemical called triorthocresyl phosphate to the "Jake" recipe as a extender.
Wow, I watch way to much History and Discovery Channel. There are many documentaries on Netflix and such about the history of moonshiners. It is an understudied part of our history I think.
However, it is my opinion that what really drives the illegality of \moonshine it the millions of lost tax revenue. But to look on the bright side at least it gave us NASCAR. LOL
Jenn