Does anybody actually believe the Assange/Snowden/Manning/BarrettBrown(hush!!) stuff is really about protecting national security?
LBJ's mistress tells all:
http://www.youtube.com/watch?v=lPdviZbk-XI&

a cult figure or merely arrogant?
Maybe both.
It's pretty pathetic that he obviously considers himself a rock star.

That's how you open the door to abuse, jurpest. When you start justifying it.
Can you think of any other public figures who acted out of courage and who claimed noble motives when they committed illiberal acts?
"Rock star" is an expression that is repeatedly (mindlessly?) used to describe Assange. Its connotations include:
Sexual virility and appeal
Alpha male
Flashy
Bad boy
Oppositional
Charismatic
Mover of irrational crowd emotions
Trace-like states
Center of attention
Less accountable for bad behavior (ought to get off lightly)
It also connotes irrationality in fans.
Is "rock star" really a flattering way to describe Assange?

I would be arrogant too if I'd helped expose hundreds of thousands of secrets and war crimes, liberated the Icelandic economy after the banking crisis, assisted in the prevention of future extrajudicial assassinations in Kenya, and paved the way for a future in which the freedom of speech isn't appended with a 'but'.
It takes massive courage to stand up to governments whilst their cabinet members publicly call to have you executed. I think this is what you're portraying as 'arrogance' (though, he has more right to be arrogant than you or I).
He's not a cult leader, he's a beep rockstar.