Should we be protected from info hazards?

An information hazard, or info hazard, is "a risk that arises from the dissemination of (true) information that may cause harm or enable some agent to cause harm".

Who's to protect us from info hazards? What qualifies someone to have the ability to keep information/knowledge from the public in order to "protect" them?

What would happen to us if all collective human knowledge was public?

How can we work towards a world where all knowledge is available without triggering self-destruction?