All good screenwriting, for example, accepts this fundamental and transcendental truth. The hero starts out as an antihero, he discloses by inadvertence his essential goodness of character to the audience, he is subsequently confronted with a situation which makes him choose righteousness against all odds over evil, which of course he does, he triumphs over evil and gets the girl.
And I think the cheesy Hollywood script writers have got it about right. The kids who sign up at the time of the revolution because the girls will look at them in their new uniforms and who, almost in spite of themselves and certainly without calculation, will go on to become winter soldiers, boys becoming men, heroes, is what the American myth is about.
Alvin York comes to mind
Bedford Forrest, I had people on both sides, is one of my heroes, but what compels people to enlist in a foreign adventure.