We're not talking about the real world, or else you should just skip the rest and follow my #8 suggestion and that would be the end of it. We're talking about the in-universe explanation up to and including all current materials preceding Rogue One, which includes AotC, RotS, The Clone Wars series, and Obi-Wan's experiences with the clones.
And while they didn't go into detail, we do know right from ANH that Obi-Wan was a general in the Clone Wars. At the time no one knew exactly what that meant and most thought the clones would be the antagonists throughout rather than originally being allies before turning on the Jedi, but the reference is still there to build on with information from the Prequels.
And while they didn't go into detail, we do know right from ANH that Obi-Wan was a general in the Clone Wars. At the time no one knew exactly what that meant and most thought the clones would be the antagonists throughout rather than originally being allies before turning on the Jedi, but the reference is still there to build on with information from the Prequels.