Warning: SPOILERS for Eternals.
The Hiroshima scene in Marvel's Eternals were created by the Celestials, which are ancient gods that create and build life within the universe. The creation of the Eternals was meant to guide and protect humanity, specifically from an evil race of beings known as The Deviants, who feed off of humans.
Each Eternal has specific powers, which help to form a powerful team with different abilities to help accomplish their mission. Ikaris can fly and shoot laser beams from his eyes, Sersi can alter the form of any material, Sprite can create illusions, Thena can summon weapons to use in combat, Kingo fires energy blasts from his hands, Druig can mind control all humans, Makkari can run at high speeds, and Gilgamesh uses powerful weaponized fists. Ajak has healing abilities (and the ability to communicate with the Celestials), and acts as their leader. Finally, Phastos is their technical wizard, able to create all manner of technological devices and inventions to help their mission (and the human race). It's here that the greatest conundrum is created with the Eternals and their involvement with humanity.
Phastos, played by Bryan Tyree Henry, is the Eternal who has perhaps the greatest effect on humanity, as he's shown to create and develop new technologies, which he "gives" to the world throughout time. It's shown early on that he attempts to create things for them long before they're prepared to have them, which is often stalled by Ajak. However, in one scene both Phastos and Ajak are seen within the ruins of Hiroshima, the first city ever hit with an atomic bomb during WWII in 1945, killing more than 70,000 people. Phastos is seen on his knees crying and lamenting that it was his fault for "giving" the technology to humanity to allow for this to happen. The issue with that type of revisionist history, however, is that it ultimately robs humanity of being human, both in success and failure, as it places the burden of both on the Eternals, while almost excusing humanity for their wrongdoings as their ability to cause harm ultimately comes from their "gods", the Eternals.
While the intention of the Eternals helping humanity with their gifts is good, the problem of humanity not being responsible for their own actions feels misguided at best and dangerous at worst. Much of this could be cleared up in showing how the technology is introduced to humans throughout the ages, perhaps more as a "nudge" than an outright schematic of exactly what they're being introduced to. While it's entirely possible that Phastos is feeling guilt over the creation of the atomic bomb the hit Hiroshima, it could've been shown that his guilt was more indirect than direct, questioning why humanity would choose this path of destruction, rather than shouldering the blame for their actions. By mitigating humanity's responsibility, both good and bad, it makes them feel like less of a race of beings that ultimately inspire the Eternals to want to save the planet and more like subjects that have gotten out of hand.
In addition to Hiroshima, the Eternals are seen in various times and places throughout human history, always mingling with humanity and living amongst them, which is supposedly where their love for them comes from, going beyond their mission to protect and guide them. From Babylon to Tenochtitlan, the Eternals witness humanity at their best and worst, with Ajak always cautioning that they can't interfere with their actions, yet multiple times, particularly with Phastos, that's exactly what they're doing. With Druid using his mind control powers and Phastos using his powers of technology to influence and guide humanity, it ultimately rewrites and retcons what it means to be human and lessens the impact of the Eternals wanting to sacrifice everything in order to save them in the end.
