To do the most damage to ((them)), look to their sources of power and what would take those away. Example: Control of money, control of power through control of leaders (social power through influencers, military power through compromised general, political power through compromised reps, religious power through control of leaders in every major religion etc.), control of information etc.

The most important is control of power, which comes down to controlling people. So the most dangerous secret would be lifting the curtain on people are groomed, compromised and placed in positions of control, the elites they answer to, the whole network.

But not in an abstract way: that doesn't produce anger without which there will be no change. Which is why I disagree with many other suggestions on this page: simply knowing doesn't change anything. Will it produce uncontrolled rage? Does it put a name, a face and a location on the target?

What people need to see is see videos of actual young children with great potential and purity being lured and the actual process of slowly psychologically damaging and corrupting them... make them go through a list of names and forced to watch what's on each one's (probably pedo) blackmail tape... video recordings of them discussing their darkest plans for the peasants... what they do for "entertainment" etc..