I do find Cora's arguments about how the military is over funded, as she is currently in the process of leading an assault on the people she is criticizing for having military. Also, considering the populations, I suspect that even if all the cores were used to fuel the Spires, with no military threat, that it would not meet the demands of the Spire.
Not saying it is not a valid viewpoint, it just seems like it was coming from the wrong person at the wrong time.