The Carver Findings are interesting, but I do worry that they are based on a number of assumptions. Even Carver himself apparently worried that by proclaiming military force to be the best solution, he guided galactic governments to see it as the only solution.

The entire Spartan project is predicated on the idea that UEG control of the entire galaxy is a good thing. If the choices are:

1) Planetary destruction on a glassed-worlds scale.
2) A few dozen kids are conscripted, tortured, and brainwashed into being super assassins.

Then option #2 looks awfully good.

But why not option 3?

3) Make peace with the Innies and allow the human empire to be broken up into individual world governments.

There are many, many historical examples of empires giving up their lands with little to no violence, from India to Hong Kong. Why not choose this instead?