Grave of the Fireflies is about Seita's failure, not the war
The persistent Western reading of Grave of the Fireflies treats it as a humanist anti-war film: Japan's Schindler's List, a statement about American firebombs. Takahata explicitly rejected this. His position: the film is about the protagonist Seita's failure of social responsibility. Seita refuses to swallow his pride and stay with his aunt. That refusal kills him and his sister. The bombs are the setting, not the moral center.
The Western anti-war film locates evil outside the protagonist: the enemy, the system, the war machine. Takahata locates the tragedy inside the protagonist's choices within an unsurvivable situation. He is not offering someone to blame. He is asking what a child owes the people still alive around him, and what happens when he cannot pay it.
The precision of the daily-life scenes, the exact weight of a rice ball, the wrong way fireflies look when they're dying, is what makes the moral argument legible. You cannot have the ethical claim without the documentary texture. This is the same instinct as Mizoguchi's long take: refuse the consoling cut, refuse the consoling reading.
Source claim: Takahata understood Grave of the Fireflies as a film about a teenager's pride destroying him and his sister, not as an indictment of the war.