@arcsalvo - that's a good point, but the author's been deliberately dancing around that in every 'on-screen' portrayal of the enemy factions. We know Ditu's military uses robots (powered by the souls of sacrificed 'peasants', of course) as the backbone of their army, and it's been noted they have a much smaller population than other empires, so it's anyone's guess how many people were actually on their ships. (Although if the numbers given are accurate, the MC might just have gotten the highest K/DR in the entire universe.)
In general, everyone in the opposing factions is portrayed as a raging asshole, even the enlisted/foot soldiers who could potentially claim to be 'just following orders', and even in the situations where the foot soldiers have been given the choice to stop being assholes, they instantly turn around and do it again. It's a very effective narrative distraction from the 'did the cooks on the Death Star deserve to die?' question in military ethics, but the general consensus throughout history has always been "if you're on a ship fighting us, we get to kill you" (but if we've destroyed your ship and you somehow survived, then we'll pull you out of the water and take you prisoner).
I'd really like to see a situation in this manhua where the enlisted crew of a ship decides to stage a full-on mutiny instead of getting destroyed by Angels because their commanding officers are evil dipshits.