UnderTaker26 "They’re an advanced civilization but still treat their people like cannon fodder and less than a bug. "
Well, to be fair: it is a world in constant war where there is no place for weak AND useless individuals.
If you don't like them as slaves, what should they do? It's not like this kind of world needs many office workers. And those office workers that are needed, need to live longer than a few hundred years to make any impact (and thus be strong).
To be exact: if planets, whole star fields and galaxies are private property, there simply is no space for short lived weak and stupid individuals.
The word "slave" is such a dark word... We imagine half naked, hungry people who are whipped to speed them up and who are used as sex objects in their "free time".
But in this world, it is simply something to enforce absolute loyalty. It is a tool to unite large parts of humanity.
And later to make enemy forces completely loyal friendly forces.
In that world there is no space for peasants who only surf the web, play online games and waste their time with other forms of entertainment and drugs... Except you have the background to support it.
Being born into a world where you need to work for someone elses benefit to survive and have an average lifestyle isn't THAT much different from being a slave in that novel.