Governments are by definition power. They aren't a reading society.
You spend two years serving. Not as a zombie, not as a brainwashed monkey. You could ring the bell and leave at any time during your service. Even active military could resign before a drop, and the only punishment was the loss of the vote and full citizenship.
You simply did a necessary job and proved you could understand the need to put the welfare of your fellow wo/men over your own. The very opposite of Ayn Rand's sloppy love letters to sociopaths. The job could be anything that was sometimes dangerous, unpleasant, but necessary and no one would want to do.
The situation in the novel described a spacefaring society that had actual, real, gosh-darned alien races that were attacking the Terrans, so a military was warranted.