Historical figures and events do occasionally get romanticized. But that's a bit different than what seems to be going on with "the Shepard." The Shepard is more akin to Beowulf or King Arthur than say... the Southern lost cause mythology of Robert E. Lee. He (or she) gets a title that makes the Commander seem to have been more than a mortal man (or woman) with human failings, and the Stargazer states that some of the history surrounding Shepard & the Reaper War has been lost.
Of course grandpa stargazer might not be an academic, but 'the Shepard' sounds like a mystic title from some pseudo-religious tale. Its hard to picture that coexisting with a society that was able to preserve its history.
I think that you're understating just how Lee was viewed in the South, especially in the decades immediately after the war. "More than a mortal man with human failings" sounds exactly like how Lee was written into books like Pollard's (or, hell, Shelby Foote's). Remember, James Longstreet and John Mosby were ostracized to the point of getting actual death threats for having the temerity to suggest that Lee made mistakes and that the Confederacy was all about slavery. There are still plenty of places in the South where the Lost Cause still survives as a sort of second religion.
But it's not just limited to the fringe loonies, either. Think of Abraham Lincoln, or Sun Zhongshan, or Mohandas Gandhi. The Camelot narrative that grew up around the Kennedy administration. The iron lady narrative that grew up around the Thatcher governments. Lenin in the USSR; Mao in China up to the 1990s (and in some ways, still to this day). As far as I know from a couple of years of teaching history, most people don't want to think about the sausage-making in history. Or, if they don't actively avoid it, they at least don't care. And this goes double for kids. If you talk to a kid about history, nuance is just about the last thing you want to inject into it, and making the entire thing into a morality tale of good and evil makes a great deal of sense. I mean, have you seen
Pocahontas or
Mulan?
And frankly,
shouldn't Shepard be referred to with a mystic title from some pseudoreligious tale? At the end of it all, the Commander was basically the avatar of all organic life, a being who was the necessary and proximate cause of the way the entire war turned out. There is almost literally nobody in the entirety of human history who has had the singular
importance that Shepard had. If somebody like that was real, hell,
I'd join a religion based on her. And given the way a lot of the events in the games happened - often with very few witnesses, many of whom would have excellent potential reasons to not divulge their information, or to have only had limited perspectives on what was going on - the Stargazer's comment about lost history makes sense, too. History can be lost if the actual records are lost, true. It can also be lost if the people who
made the history didn't feel like talking about it.
So yeah, I think that there are plenty of reasons that make the way in which Aldrin's character set his story an eminently believable one.