In the shared mind of the Anu, it had always been difficult to keep secrets from each other, or to do one another harm.
This was still true for the first few eras of their stay on Earth, but their telepathic connection had always been based in logic and mental clarity.
Using emotion, the small group of paranoid military managed to hide their greed and growing hunger for power from the others. They planned a rebellion in a way the others never thought to look for. They plotted, stole from the scientists and tried to accrue power, then they forcefully took control.
The scientists, even though they were the vast majority, didn’t stand a chance.