So this is what I can devolve from watching the finale now without reading others opinions yet(
@AOS- I haven't read yours yet but I will after I post this)
To me it seems as though that the real villains were actually the Cantus possessors . Not only were they the cause of destruction in the ancient civilization but the Queerats were the creations of the Cantus possessors by making normal humans into a sort of servants for the Cantus peeps. Hence why the fact was hidden so well and the false minoshiro couldn't even answer such a question. That's something Squealer probably figured out in the end and fueled the rage that was left by the ancient civilization into the war he caused.
So the bigger picture I saw was that the Cantus User Superiors like the Board of Education & Ethics Committee were pretty much trying to stay superior hence the granting of the title of "Gods" by the Queerats by disposing anyone & everyone who tried to step in their way and even went through such lengths to manipulate minds and memories. The Cantus peeps were merely trying to play God in my eyes after thinking about it now.
Squealer probably learned all about this and intended to disrupt such order.
Those minoshiros were a problem.
EDIT: Aiding what I just said, it all connects how the Queerats are actually humans but ones that merely don't possess the ability to use Cantus. Their intelligence, behaviour and symbolism in the series, even the way the Queerats replicate the evolution of human civilization all connects. The ace in the hole was the DNA twist they threw in and the tseudo item that connects to that was Saki's workplace when she turned 26, it looked as if her workplace was farming Queerats like experimental mice.
Jolly good I say