Yes, one of them, the other being that he published the full documents and not just stories using them as a source.
> you think makes him worthy of prosecution
It was so obvious I would get downvoted by Assange stans for answering the GP's question, that I literally preemptively stated I wasn't saying this. Wasn't enough apparently.
You have linked to the version published after Senator Gravel made them public domain by submitting to the congressional record - nothing comparable happened prior to Wikileaks publishing it's material.
There is no content difference, both contained leaked documents and articles about them, the only difference is the limitations of the medium.
"The New York Times began publishing excerpts on June 13, 1971" -- https://en.wikipedia.org/wiki/Pentagon_Papers#Leak
Assange is also accused of assisting his source in attempting (unsuccessfully) to crack a password hash, thereby (the prosecution alleges) taking on more the Daniel Ellsberg role rather than the Washington Post role.
Not commenting on the appropriateness or not of prosecuting Assange, but the situations have significant differences.