Why is the knowledge on how to make meth the most dangerous knowledge you can think of? The difficulty in making meth is that, due to the war on drugs, the chemical precursors, specifically methylamine, are illegal and hard to procure as an ordinary citizen. This was popularized by the show Breaking Bad but as far as I've read, is actually true. It seems there would be other bits of knowledge/ideas that would be more poisonous that corporations don't want to promulgate. Ideas like the Jews secretly control everything or that white people are better, are probably not views that corporations or society want an LLM to reinforce and radicalize people into believing, among others.
