Knowledge being thrown around without understanding the implications of how that knowledge would be acquired. School systems in our world have really made most people believe that knowledge is just given and easy to come across. Like how many people drank lead because pipes were made of it before we figured out why that was a bad idea.
Most of the time, it's medical information. In our world, an extremely large amount of our understanding of the dangers and symptoms of disease progression came from the Nazi and Japanese experimentation on human test subjects during world war two. Without throwing anyone under the bus, I dropped a novel recently because they were trying to portray demons as a sympathetic race that were actually humans who've succumbed to a disease. Except the demons knew, down to the minute, how long you could go without taking an antidote before you'd succumb as well. Along with various ways the antidote could be taken, and how much matters. There aren't any other humans portrayed as living among the demons, which has some incredibly evil implications as to how they figured that information out.