There's still something I don't quite get. Yes the MC never raped any of them, but he ulti...

the humans are adventurers who came upon the ogres and were defeated. They saw benefit in staying with the ogres after being captured and even leveled their skills to be better than what they would be. Also they came to fall in love with the leader and happen to be content with living with the ogres. They are only thinking of their troop and not of home,where life is way harder since as an adventurer,you'll have to go through dangers to make a living. Most adventurers dont stay with their parent anymore.

as for the elves,they were enslaved because they came to attack with bad intentions not wanting to give up. I think they were given aphrodisiac to give in to lust. And as prideful as elves were,after being tainted,they wouldn't want to head back home even if they could. + i think they might have sworn to the leader to follow him. the female slaves have accepted the ogres way of life now and are content with the way they live. so its not enslaving the other race anymore although they didn't have a choice to leave in the beginning as such was their punishment. You just gotta be part of it to be freed from the punishment.

That's the problem I have with this manga too...

Why leave when you get much better living opportunities when you stay. As far as I can tell the motto is "You don't work, you don't eat." Where as the motto outside the goblin community is "Every man for himself,unless you're a noble."

That is what you call stockholm syndrome. It is a condition that causes hostages to develop a psychological alliance with their captors as a survival strategy during captivity in the end those feelings are assimilated by the hostage making them feel at home without that being true. In some cases the victims are capable of "changing factions" and strat seeing their old acquaintances as new enemies. Hope you understood ٩(๑❛ᴗ❛๑)۶

Point taken but consider this. If one is given the option of either:
1. Stay and be protected. Learn and get stronger. Be given food, clothes, a sense of community and a job. The sex is an added bonus.
Or
2. Leave and hope you can make it to a human settlement without being robbed, murdered, or raped by monsters, demihumans or humans. No job security and if you tell people what happened they might declare war on the goblin tribe and kill your friends and benefactors.

But above all remember, this is make believe!! I mean the guy eats his own kind and the treatment of prisoners is your greater concern?

it has nothing to do with stockholm syndrome. nowadays ppl just keep making out everything as a psychological sickness to justify things. if they werent monsters but humans, they'll be treated the same way after being captured. even then the treatment they'd get is far worse because humans tend to make the lives of their opponent much harder,working them out as slaves for themselves to prove their power so others submit to it or at least wouldn't want to find themselves in that situation.
some people really need to quit saying everything is stockholm syndrome when its a fucking strategy to have the enemy to not fight back.

Lol yeah the fact that he's a cannibalist completely slipped my mind. Honestly though if I had the consumption ability, I'd do the same. And as disgusting as it is, in a real life situation, if you were starved to the point that you're not thinking straight, can you say you'll never eat human meat? I can't simply because I can't guarantee I'll be able to say no to food in a life-threatening situation.

Except for the male humans. If they are not smart, strong and good looking, they ended up on the dinner plate.
Male elves at least were kept alive as sex slaves and sperm banks.

Sorry if this is too latr of an answer but here is my shot at this.
1. Human males (the poor priest) and male Elves were kept alive for sperm banks and sex slaves.
2. Ogarou every day gave them Aphrodisiac, to help to make sure they didn't die. And because he remembers the woman that he freed in the beginning (killed) he doesn't really force them. He would have killed them if they really didn't want to be sex slaves.
3. Second the human woman and men that were captured as sex slaves had the same thing happen to them. The rest were only prisoners of war, therefore technically not many humans were kept. For regular war reasons not enough rations to feed them and because they have no use for them if they are ugly and weak reason weak offsprings and personal preference. Reason why not many human males were kept.
4. The reason Elves don't go is because one: for the Elves they had already accepted Ogarou as their leader. They understood they were goods of the war. The stupid Prince (their leader) was dead. Had peircings. (Considered a shame in their culture.) And the earrings on their ear is an obedience earrings, they probably don't want to be used as spies, and he let them see the sacred ceremony of the dead, meaning they still have privileges more than any casual sex slaves and are allowed to train their rank.

5. The few remaining humans on the other hand, yes they have privileges, since even though used as tools like a chess piece at one point, they are still allowed to train.
6. Some humans did leave at some point after the war was over, but I'm guessing the few humans that stayed for the same reasons as the knight chic and dude, they respected more the society of the Goblings then those of their own culture. Some of the chics got pregnant I'm guessing they either want to stay because of their babies or want to stay until they give birth to the babies so to leave them behind. Most of the humans were of high society rankings most I think feel wrong to go back home the way they have become after the war. Even though they will have high social rank once back home, they are not mistreated, are allowed three days off every week, so they can be trained to do anything, having new lives with the Goblings.