Realism:
We all know that the American Civil War happened.
Josey Wales was fighting with a bunch of blokes known in real life as Quantrill's Raiders (QR's). If you remember in the film they carried a black flag. There is some debate as to whether QR's actually carried a black flag but it is certainly reported by some that they did.
Bloody Bill Anderson was a real person who died in a Blue Scum Bellie ambush towards the end of the war.
QR's came from (in the main) and were based out of Missouri. However, Bill Quantrill himself was from Kansas. Now Bill hated Kansas as he was thrown out of the State prior to the War starting because of a few incidents of a dubious nature carried out by Bill. So Bill didn't like Kansas or any of its people.
The Redlegs were based out of Kansas.
Both bands had quasi recognition as 'forces' in their repspective armies. QR's = Confederate, Redlegs = Union. However, here again there are conflicting opinions as to the actual command status of the Raiding Forces (North or South).
Were they saints ? No, both organisations (QR's and the Redlegs) have been reported and documented as doing some not very nice things during some of their raids.
Did both organisations qualify as War Criminals ? Only the losers are criminals, whomever wins a war are the 'good guys' and thus it was post- the American Civil War. Quantrill's Raiders were vilified by the North. Quantrill himself was shot and died of wounds at the end of the war itself. General Lee, I believe, had already surrended but Bill Quantrill was unaware at the time he was shot and mortally wounded.
Jesse James and his brother Frank, plus the Cole Brothers, rode with Quantrill's Raiders.
So, there is a genuijne reality in the film which gives it an immense amount of credibility. Things like that (what happened to Josey) happened during "that damn war". And as in all wars, atrocities happen on both sides whether you are the winner or the loser.
Reality = Credibility. And the fact that Josey fought on the losing side in the American Civil War gives the film more relevance as Josey fights his battles for justice.
Regards,
Wombat