On the face of it, Cultists sacrificing the worlds they lived on to Chaos seemed horrifying, foolish, and deranged. In reality, a great many worlds did exactly that.
To ordinary people, the Imperium was a pile of shit, and so was Chaos. They had no way of telling which pile was more evil or harder to stomach.
Most ordinary people lived in hunger and cold, working more than ten hours a day just to feed themselves, only to be berated by their overseers as worthless burdens on the Imperium.
On top of exorbitant taxes, the Department of the Interior, the Adeptus Arbites, the Inquisition, the Ecclesiarchy, and the Imperial nobility all claimed to protect the Imperium of Man. The price was always the oppression of ordinary people.
In such darkness and despair, a voice from Chaos told an ordinary person, "Your life is shit. You are free. You can choose something better."
"No power? That doesn't matter. The supreme might of Chaos will help you. All you have to do is offer up that insubstantial soul of yours."
Once they surrendered that insignificant soul, they gained the power to kill those who had bullied them and seize greater authority.
They no longer had to eat lime-like corpse starch. They could enjoy meat, grain, fruit, and fine wine. Do well enough, and they could even kill nobles and governors, cut off their arrogant heads as offerings to the Chaos Gods, and enjoy their glittering hoards of wealth-as well as their beautiful wives and daughters, whose skin was as smooth as silk.
It was a carnival, a process steeped in madness, bloodshed, and immorality. But how many ordinary people in the 40k universe could withstand such temptations from the Chaos Gods?
The worlds sacrificed to Chaos, one after another, and the madly