Jesse was a VERY impressionable young boy of about 15 or 16 when he came under the influence of Bill Anderson. Then he came under the influence of Archie Clements. Jesse's post-war fame came about due to his own very considerable cleverness, plus the complicit help from "Major" John Newman Edwards. Now....Edwards was a very capable Confederate cavalry officer and adjutant to General J.O. Shelby. But he was a die-hard, seemingly unapologetic rebel. He saw Jesse supposedly continuing the fight, and he jumped willingly into Jesse's media spin. In fact, he CREATED most of Jesse's media spin, and he helped Jesse propagate anything that Jesse didn't create himself.
As far as I am concerned, I think Frank is by far the more interesting of the James brothers. That's because I never swallowed any of Major Edwards's spin. Major Edwards was a fine adjutant with a fine intelligence network, but he was a newspaper editor with a personal agenda, and there can be no doubt about that.