I agree that certain versions which I've identified as rebel versions can be interpreted as John Henry expressing pride in his ability (and in his determination to defeat his opponent in a steel driving contest, whether the opponent be a steam drill or the captain or any other challenger.)   Unfortunately, I failed to note in my original post that these versions are open to different interpretations. I get into this on my webpage which can be found at:

https://sites.google.com/site/johnhenrytherebelversions/

or by googling "John Henry the rebel versions"

Most of the informants for these versions were African American, and I believe that a large number of black men in the early 20th century Jim Crow south would have interpreted phrases such as "before I let you beat me down/before I work from sun to sun, I'll die with a hammer in my hand" as a threat to fight back.