A demagogue/ˈdɛməɡɒɡ/ (from Greek δημαγωγός, a popular leader, a leader of a mob, from δῆμος, people, populace, the commons + ἀγωγός leading, leader) or rabble-rouser is a leader who gains popularity in a democracy by exploiting prejudice and ignorance among the common people, whipping up the passions of the crowd and shutting down reasoned deliberation. Demagogues overturn established norms of political conduct, or promise or threaten to do so.
Historian Reinhard Luthin defined demagogue thus: “What is a demagogue? He is a politician skilled in oratory, flattery and invective; evasive in discussing vital issues; promising everything to everybody; appealing to the passions rather than the reason of the public; and arousing racial, religious, and class prejudices—a man whose lust for power without recourse to principle leads him to seek to become a master of the masses. He has for centuries practiced his profession of ‘man of the people’. He is a product of a political tradition nearly as old as western civilization itself.”
Demagogues have appeared in democracies since ancient Athens. They exploit a fundamental weakness in democracy: because ultimate power is held by the people, it is possible for the people to give that power to someone who appeals to the lowest common denominator of a large segment of the population. Demagogues usually advocate immediate, forceful action to address a national crisis while accusing moderate and thoughtful opponents of weakness or disloyalty.
Socrates basically was killed by a democratic decision of 500 Athens.
… the silent way to revolutionize mankind (= aka the world) can be a growing awareness of what lifestyle changes are needed to be done in order to allow a sustainable future and secure the survival of mankind.
You do not have to kill anyone for this – a little boring – changing your own lifestyle – bit by bit – step by step.
growing vegetables yourself (of course needs a piece of land? where to get it form? you will have to fight hard for it, this is where violence probably occurs) but also studying science and developing technology that allows humans to travel to distant planets and settle there – would be such thing.