Okay because I am seeing it constantly, arguments like "adapting and changing stuff is okay and in fact necessary" and "was Troy more accurate, why did you not complain about it haha", I think there is something very obvious that you are all missing or choosing to ignore.
Not all adaptations and changes are equal.
An adaptation in which a hero, who is viewed largely positively within his country, is used as a scapegoat for things of a larger and very much real historical scale that far exceed his strict responsibilities as documented in the oral tradition of his country (end of Trojan War and associated matters) is not exactly an adaptation, it is flirting with offense. Nolan really lectured that the Greeks were responsible for the collapse of their own civilization and all the late Bronze Age Civilizations, which is obviously something he pulled out of his ass. In his exaggerated take on the social contract, it seems as if the Greeks are responsible for the greatest violation known to the Bronze Age, which therefore results to its ultimate collapse, as if warring and attacking cities was not a frequent occurence amongst the ancient peoples of the time.
We know that a possible Trojan War may have contributed to a period of recession in Late Mycenaean Greece but this was only a factor in the grand scheme of things that caused the Bronze Age civilizations to go through a period of stagnation and decline. Others were natural disasters (including great earthquakes, volcanic eruptions, droughts), diseases, the change of sociopolitical and economical dynamics and of course the Sea Peoples.
Nolan points his finger to the Greeks, almost like he's in a sermon, and tells them: "You all paid for sacking Troy". He attributes a real historical decline to divine or cosmic punishment for a legend that may or may not have even happened in this exact way! And not only this, but he also blames the Greeks for the decline that befell third countries during the same era and interprets the Sea Peoples as an exclusively Greek catastrophic group of people! Meanwhile, historians know very little about the Sea Peoples, except that they were most likely something like early pirates, comprised by multiple ethnic groups, ONE of which was also the Greeks, and as one may assume, marginal delinquent people and not their most celebrated men!
Some people say "it's a mirror for the wrongdoings of the West", well if he wants a mirror for self-reflection and presentism he is free to create an original American / British story or draw from actual American and British history, I am sure he will find plenty of content there. And he can leave the Greeks alone.
I am not illogical, I don't expect a hagiography of the Greeks of course. I am not at all opposed to showing the atrocities the Greeks committed in Troy, because those were things already acknowledged and documented by Greeks themselves. There is great difference between this and what Nolan does, who puts the blame for an entire collapse of the then known world on the Greeks without any historical evidence for that! (Let alone that it is completely ahistorical to ever suggest that a single nation can be responsible for a total collapse of civilization.)
And since a lot bring up the inaccuracies of Troy, watch this, the mere 13 minutes of Odysseus scenes in Troy:
There are a ton of inaccuracies here, including the glaring "cousin Patroclus". Yet look how Petersen's Troy understands or respects the homeric epics more earnestly:
Odysseus is immediately and efficiently established as an intelligent, cunning, adaptable, inventive man who changes his arguments in order to achieve his goal, which is none other than to return quickly back to his home and family without angering the other Greek kings (and the way to achieve that is to achieve a quick victory in Troy). Of course the victory was anything but quick but this Odysseus' motivation is consistent to the characterisation of Homeric Odysseus (who did not even want to go to this war). In 13 minutes Petersen and Sean Bean give an Odysseus Damon and Nolan could not give in 3 hours.
Of course we also get an accurately angry, proud and narcissistic Achilles and a greedy and explosive but HUMAN Agamemnon, who discusses his plans and strategies with the other Achaean kings. And not a war comic caricature.
Notice how Wolfgang Petersen had the skill to present Mediterranean landscapes accurately as luminous and beautiful without this removing from the impact of the violence and the tragedy.
Notice how Troy can keep audiences engaged in the plot and the fate of the characters without having to force the Greekness out of them. Count how many times the words Greece and Greeks are spelled out in these mere 13 minutes and compare it with that in Nolan's Odyssey, in which you almost feel the two? times the word Greek was uttered was out of sheer and overbearing obligation.
Moreover, look how Achilles, the demigod, the most proud and glorious of warriors, says in Troy that "Greece was fine before me and Greece will be Greece when I am gone". In short, Petersen recognizes that he tackles a mere element of another culture and he treats said culture with respect and gratitude. Achilles is an element of Greece, not Greece an element of Achilles! This is the EXACT opposite of what happens in Nolan's Odyssey, where the wrongdoings of a single man, Odysseus, are capable of destroying the entirety of the Greek civilization and beyond!
The last scene of Odysseus as narrator is also the last scene of Troy, not accidentally, since there were many hints throughout the movie that there were intentions for an Odyssey as a sequel. We greatly missed the chance for a Sean Bean Odyssey. It would have been a good one. But these last words prove that Petersen and all the cast and crew involved understood what the Iliad was about. Odysseus says: "Let them say I lived in the time of Hector, tamer of horses. Let them say I lived in the time of Achilles...". Apart from the clever tragic irony and foreshadowing here, in which Odysseus expresses humility and awe towards greater men than himself, while we know what he still does not know about himself, that with his journey back home he might even become a greater legend than the other two, it is crucial to stress that this is the very meaning of the Iliad; it is not an anti-war manifesto in the way we understand those in current times. It is a study on hysterophemia, meaning "posthumous glory", a concept that has had great significance to the Greeks of many eras. The Iliad does not give us a clear answer and neither does Troy. Was it worthy after all? And then you have the brilliant sequence in the Odyssey, where the ghost of Achilles tells Odysseus that he'd rather be a plain random living man than the most glorious amongst the dead. So, there is of course a pondering, a questioning of war and violence, but it is not so much through our present moral compass, but rather through the realisation that life is ought to be celebrated instead of given away over petty emotions and ambitions. And yet, the very fascinating irony that Troy highlights is that Achilles' petty ambition was not fruitless. He is remembered and discussed thousands of years later. Still, is it worth it? Odyssey gives an answer but it's also left open to anyone's interpretation. And this is exactly how Petersen elects to bring closure to his movie, in complete harmony with the homeric epics, despite the countless inaccuracies and liberties he took.
Therefore, Troy might be full of inaccuracies but it shows respect and understanding to all the major points that matter the most. Despite its inaccuracies, it also manages to remain sensitive towards the culture of origin of these stories. Even if there is no Greek acting in it, all the actors really make you believe that they are Greeks and are concerned and proud of their nation.
Meanwhile, Nolan makes a double choice of both putting said culture on the spot with an ahistorical conflation of legend / myth and later historical events and also attempting to erase said culture as much as possible, in order to make the story about his own present or at least more recent culture. I don't think Nolan's interpretation is bad as a concept. It's actually very interesting, but this does not change the fact that it is self-inserting and culturally insensitive towards a nation that is foreign to him.
Conclusively, yes, you may adapt and change stories, but adaptation from adaptation can differ greatly and not all are bound to be received in the same blindly positive or negative way.