What purpose does distributing information on explosives provide other than creating knowledge of how to create explosives something which most people don't have an actual need to know how to do, regardless of how trivially way it is to do. Someone the next town over destroyed an entire condo complex killing himself making improvised explosives.

I agree, myself knowing how simple it is to make IEDs from home devices (I was in the military and defusing IEDs, mines, etc was part of my MOS), that the line between explosives and propellent is tenuously thin if at all present. The issue is the intent of dissemination of the information. What possible reason other than making devices that could put people at risk provide to the public? He was intentionally putting out information to attempt to cause harm to other individuals and the right to life is primary before the right to liberty in the Constitution. A bomb is not a self defense tool like a firearm. It's not useful for controlled demolitions. It's sole purpose is to cause fear and harm to others. That's why it doesn't fall under protected speech.