I think we said mostly the same thing, and agree on the basic point that people are complex. I don't want to get too far into a discussion of real world cosmology, theology, or normative ethics that would have to be a part of talking about applying the idea of alignment to the real world, because invariably that would get religious or political or otherwise get people triggered.
Well, those actions are far more detailed and spectacular than your original statement, which was only: "an upstanding citizen who would sacrifice himself to save the community, helps little old ladies across the road, donates money to help orphaned children". To be honest, you complain about how someone who is perfect being a caricature, but I'm not sure that Dudley Doright is less of a caricature than your upstanding heroic person who is also and at the same time a depraved serial child abuser, and who is quintessentially lawful good but also and at the same time engaged in repeated acts of depravity. I'm not convinced such a person is more realistic than someone whose worst faults are so minor, most people wouldn't even consider them flaws in their own character.
I can imagine a hero like you suggest with dark secrets, but not to the degree of depravity you suggest. Your upstanding citizen who is quintessentially lawful good cannot be quintessentially lawful good unless he knows both what honor and depravity are, and therefore cannot both be who you say he is and not know who he is. The mental stress he would be in trying to live his life when the poles of his life are so far apart would be lethal. I don't think there is any real world person who can endure the degree of division you are talking about.