"A Jedi uses the Force for knowledge and defense, never for attack"

I was pondering these words recently... More specifically, relating to how the Jedi moved from the zen-like mysticism they held in the OT to a an arrogant and hostile pantheon in the PT, little more than an extension of the ineffective and corrupt Republic that they defended.

And I realized, after some reflection, that no true Jedi ever attacks anyone in the films. Yes, Luke, a Jedi-in-training, uses his force powers offensively at several points during the films, but those are all excusable.
-In ANH, Luke is not yet trained in the ways of the Force.
-In ESB, he attacks Darth Vader against the wishes of Yoda
-In RotJ, he is struggling against the dark side for most of the movie and, thus, not acting like a proper Jedi.

But a by-the-book Jedi never attacks anyone. Think about it for a second: what was stopping Yoda or Obi-Wan from going out and actively helping the Rebellion? To assist in taking down the menace to the galaxy? Absolutely nothing. If he'd wanted to, Obi-Wan could have hopped on the first transport out of Mos Eisley, made his way to the rebels and assisted them. But he did not. Instead, he waited patiently and only when the rebels felt the need for his guidance (and not his force-imbued brawn) did he move to assist them. His fight with Vader was never about aggression; indeed, he never makes a move to attack his former apprentice and stands calmly as he is struck down.

Same deal with Yoda. At any point he could have gone out and joined the rebels in their fight, lending what expertise he could, but he never did. Why? I have a sneaking suspicion it's because the Jedi were never meant to be adventurers, skipping across the stars on swashbuckling adventures. They were meant to be humble, wise and, most importantly, non-violent. If you think about it, that would explain why Obi-Wan said that he could not interfere with Luke's duel with Vader and why he never acted as some glowing blue spy: not because there was some supernatural Dues ex Machina barrier keeping his spirit from supporting Luke or materializing in an enemy command post to glance at some sensitive information, but because those would both be forms of attack. Well-intentioned and completely justifiable attacks, but attacks nonetheless.

So what point am I trying to make? I think one of the reasons the Jedi seemed so different in the PT, aside from their crappy attitudes, was that they were doing something the OT Jedi would never do: they were fighting. They were not defending themselves from street thugs or using mind tricks to avoid violence... they were leading assaults on enemy positions, participating in battles against other soldiers, hunting down ridiculous four-armed asthmatic droids who learned lightsaber arts from a drunken Count Dooku doing his best impression of a windmill. They were ATTACKING! The Jedi were meant to be monks, not warriors, and that is what the PT changed.

Not that Lucas would ever admit this of course. Whether or not he ever thought that, he clearly changed his mind by the time the PT rolled around. I suppose, to give him credit, the concept of Anakin fighting in the clone wars is as old as Star Wars itself, but the OT never really goes into his capacity in that respect. It could be that he, like Obi-Wan, was originally intended to be a general, offering advice from afar, or just defending worlds that were under attack. Given that the details of the Clone Wars weren't even concrete at that point, it's possible they were originally going to be a totally different type of conflict altogether, one where the Jedi may have been forced into combat due to circumstance (say, a galaxy-wide genocide by clones).

Just my observations. And me trying to start up a discussion.