[Guido]

I'm not going to resume the old arguments from previous comments rather to express my personal interpretation on how I see the setting of Attack on Titan has surprisingly expanded, given that the revelations unearthed from the basement drastically have altered the game change whether for good or for bad.

While history is written by the victors and the side of the story from the losers gets concealed for posterity or fades into oblivion, the cold hard fact is that human nature has never changed and conflicts through war and/or violence for domination as the end game are proof of that bloody history.

Who is to say that Marley exaggerated or revised history to paint Eldia in such a deplorable reputation?

Who is to say that the rest of humanity (without exception) wants the Eldians wiped out as Sergeant Major Gross replied to Grisha?

Who is to say that the founder Ymir Fritz delivered wealth and abundance to the Eldians when Grisha could have had extrapolated the data from the records he deciphered with his own personal interpretations and feelings?

Facts are immutable, but the truth is not given that people can hold the monopoly over by declaring how self-righteous they are while condemning others who do not agree with their opinions.
The latter has happened everywhere in each previous century.

The facts within the story and setting of Attack on Titan are:
1. Fay Yeager was killed and mutilated by Gross and his sons for sport and recreation. The justification was she was an Eldian that went into a no space for Eldians zone without a permit.
That was just a pretense for Gross to justify himself legally as the other Marleyans most likely wouldn't have bat an eye over the issue but be gladly overjoyed to themselves for what Gross did had the truth gotten leaked into the public.
Gross did what he did because he had power to abuse it freely to his own discretion as a means to vent his desire to dominate and inflict misery upon a helpless, little girl.

2. In a mainland continent, the nation of Marley keeps Eldians confined into interment zones and/or ghettos letting them live as third class citizens.
The irony is, in spite of spewing their toxic rhetoric and hatred against the oppressed Eldians due to the Eldia Empire transgressions and genocide policies against the Marleyans in the past, the Marleyans still turn Eldians into mindless titans for two reasons:
a) As seen with the potential insurrection of the Restorationists and the Ymir cult, for capital punishment way worse than death to ship any troublemakers, then turn them into titans, and let them roam Paradis for eternity.
- They kill two birds with one stone with this approach as Marley can continue to exert control and dominate the Eldians living in the continent as well as keeping the Eldians living within the Walls caged with the transformed titans released into the island.
b) Just as Grisha explained his opinions on Marley designing an attempt to obtain the Founding Titan from Paradis, at the world's stage Marley is a nation competing against other countries for resources in order to exert their hegemony and domination in global affairs. Hence, it makes sense for Marley to treat Eldians as assets to be turned into titans for war power to be used in the battle field.