Well, attack means you want to change the world. It means you are rejecting the reality in front of you, and enforcing your desires on it.
Defense means you are trying to enforce your desire to not be attacked.
One is imposing your will upon others, one is not. The Jedi are against the imposition of ones will on others, whether that is you imposing your will on another, or another imposing their will upon you. Resisting the imposition of will upon you is not the same as imposing your will on another - it is reactive, not proactive. So long as one can avoid being provoked into a backlash of revenge or feeling threatened and go further than simply pushing back enough to remove the imposition of will, then you remain defensive.
The Jedi are against imposing their will on others, except when it comes to dispensing their personal interpretation of justice or rounding up really young children to brainwash them with Jedi doctrine.