Yeah, but the American soldiers who lost in Vietnam also fought despite Vietnam posing any serious existential threat. The point is that he has a foot in the human world, he is operating for the American state, and this highlights that.
This is the point, he acts like a fucking midwit burger except he's invincible now. Other than acting cold what fucking effect did being privy to every fucking secret of the universe have on Dr. Manhattan?
This is why Greek and Christian Gods are so timeless. They don't have these yawning gaps in their own logic.
I get that sacrificing a a few 100 thousand people might be justified to prevent a nuclear war that kills billions but the Vietnam War was a farcical war that MILLIONS OF PEOPLE KNEW AT THE TIME.
Regular comics avoid these problems by having their own made up politics.
One critic I linked said that Moore has a nostalgia for Nixon and even Reagan to an extent. This rings true and is the only explanation for Moore's confounding choices for his alternative history.
Many Anarchists harbor have this reactionary sympathy for fascists. And it's in Moore's comics. They're like Pit Mommies that think prejudice against their dangerous dogs are allegories for prosecution of marginalized people.
I agree with Moore's subtext that it's silly to think that super hero's with the power to shape society would be good and ethical because, well just because! But then he makes equally absurd claims that superheroes would all be irredeemable asswipes because society mmaaaaaaan.