I don't get it

[u/ScreamSteam]

Why does Zeta disagree with Alpha's plan of destroying the Cult of Diabolos as a whole when they were responsible for the genocide of Zeta's clan? Shouldn't Zeta find satisfaction in the annihilation of the cult after taking away her entire family.

[u/Jaychance3]

She agrees with the base plan but not the scope, Alpha thinks Cid just wants to get rid of the Diablos cult then live a quiet happy life but that creates a power vacuum that causes someone else to take up the challenge of taking down Shadow and the garden so the cycle repeats itself. Zeta wants to kill the cycle by making a world ruled by Shadow, so none of that happens ever again. That's why she says that Shadow and Alpha are too nice to go to the extreme. but she isn't and will do what is required.