In an oligarchic world with centralized power structures where few have power over the many, we make a system with centralized power structures where few parts have power over many.
The internet won't be democratic and decentralized until the world is.
They were expensive but fast enabling and encouraging raiding of neighbors and riding away before they could rally a defense with far less risk for the reward compared to a band on foot with melee or ranged weaponry who would get beaten or cut down and either enslaved or executed if they attacked a village on their own.
It may have been existing flawed morals to consider raiding then but the power influenced them.
Horses didn't cause cavalry, horses were domesticated and bred with their modern properties because people wanted cavalry. The tool reflects the creator.
There are only killing machines.
There is no decentralized information technology.
The are only information technologies.
The capabilities are loosely determined by the creator; the result is determined by the user.
Consider Bitcoin: fully decentralized in theory, yet in practice controlled by an oligarchy.