Based on what you said, that humans would less inclined to eat cows if they shows any signs of intelligence to built homes and express their feelings. Well, imagine this: maybe there REALLY are cows like that, but since they only served for elites like presidents and gods, how could we know such cows exist? Imagine those intelligent cows escaping and meeting fellow intelligent cows and PLOTTING to massacre human so they can live freely.
In this story, the majority of common demons (whose train of thoughts are yet to be revealed) only know human meat from the mass-production factory, that are lifeless, thoughtless, feelingless. Demons also has structural society that is ruled by a bunch of elite that are the only ones fully aware that intelligent human exist and enjoy killing them. Can you still say "KILL THOSE CLUELESS DEMONS!!" for the fault of their FEW cruel elites?
you clearly do not know anyyhing abouy nazis and how they started and then how everyone in germany were forced to join them or put in camps like how north koreans now are , nazis had normal people as well who only jooned nazi ruling party so they can survive and for their families to be spared , they were good people but in war when people fought against them they didn't say no let good nazis go their some good nazis , all nazis were condemded and irradicated and right now anyone who want to express nazi ideologies is being threated as threat and investigated , same for isis , do you think normal citizens in isis controlled areas were left alone or were they forced to submit to isis laws or they would not be left alone or spared , but when the national defence army fought they killed everyone the good and bad cuz they wanted to gain the control of area back , this is reality .
You know that most of the meat you eat is made in factories just like those kids are in. Most of the meat you eat the animals are die, raped, and live their whole lifes laying down, if you can call that okay.
I'm not saying they are clueless, I'm jist saying that like most of us, commom demons just want to survive and live with their families. Of that's wrong then us eating meat is also wrong.
But if they tried, they could try to create a substitute for human meat with Musica's blood.
My point is that you shouldn't kill everyone just for revenge or without knowing them, ir makes you no better than the demons. There's some demons who just want to survive and live happily, who have nothing to do for the elites. You don't know everyone single demon to give them all the same label. Maybe there's more demons like Musica.
correct me if i'm wrong, but i get the impression that you missed the point of my last comment.
I was talking about how the common demons MAYBE don't have any clue that human is as intelligent as they are, (heck maybe they themself don't know what will happen if they don't eat human meat) therefore they (JUST LIKE US eating meat) doesn't see it as inhumane or cruel to continue eating the mass-produced human meat.
my point is, maybe the common demons are clueless and innocent, unlike the cruel top-of-society demons they meet so far. that's what i get from the story.
I won't talk about how our meat were treated since it's out of topic here.
You still miss my point: They could not have BECOME like us without eating humans, and apparently most will degenerate (not hold form) if they stop eating us. In other words, how do you solve that fundamental issue? The ones that want to maintain form and intellect are not going to stop eating humans. Vegetarians do not lose intellect or form by not eating meat. It's a choice, not a necessity.
If they can solve that desire and need to eat meat, fine. But I'd not be very optimistic.
I'm afraid their cluelessness is still an assumption until proven wrong.
From the time Emma disguise herself as a demon in a demon market, the scene right there is important, because the way human meat is distributed among the common demons is no different than how we buy our meat. From there, I cannot see the demons as merely a bad species, there's good demons as well, just like human in general (we have bad human too, right?).
For me, there's no way a mangaka that's able to create a story like this, making the characters black and white, good and bad. That's why, we already have:
bad demons fully aware of the situation (those elite demons, farmer, & their minion)
good humans fully unaware (cattle children & human world)
good humans fully aware (Emma & co)
good demons fully aware (Musica)
bad humans fully aware (ratri clan)
wild demons (neither bad or good, just instinct)
yet to be known (except maybe known only to Emma as the only human ever walk in a demon town and the only human sensible enough to observe them objectivelly):
good demons fully unaware
And, btw, that's not to say that the theory is not correct. :) I'm assuming that it would make heroes villains to kill those who assisted them without an attempt to find a truce, a way to coexist. What I'm saying is that those who have been raised as meat, who have had intense losses, I understand desire to obliterate and avenge. Because they only see they are in danger. They are to be eaten.
And in a way Norman is right: If he didn't have his assasins, Emma would now be dead. They rescued them. They'd be in a demon belly by now without his assasins. And his sole mission is to save HIS OWN...his family. He doesn't really give much of a shit about much beyond that. It's sort of like a mother who has had half her children killed by a ruthless enemy, and cannot see "gray." All they see is: I will do what I must to keep what children I have left alive. If that means I kill everyone who is a threat and demons= threat, then demons must go.
That mentality given what he went through (even after leaving the house) in order to survive is understandable. It will take Emma et al to help Norma find "the other way" if it exists (it's a heroic journey, so I assume it must exist, hence the helpful demons). Dramatically, Norman is the one who can only see one way, but may be the one who can facilitate the other way (ie, through his genius).
But do I get the reasoning "kill all the human-eaters." Shit, yeah.

I love Emma so much and with chapter I just love her more. Genocide is wrong no matter what.
I would do anything for her, she's so kind and I just want to hug her.