I just finished a great workshop with the Labyrinth Theatre in New York. I had decided to become involved as a way of recharging some of the batteries.  It worked. I discovered that using new eyes to examine something that you have been doing for a while allows you to learn and relearn what you assumed you knew already.  It may be true.  We do know things. But, circmstances change so what we think we know has different implications.
But, this is difficult when it comes to long held beliefs that may fundamental to the socio-political structure of our being. Peace is better than war, yes but conflict and struggle bring change. World War 2, ending apartheid in South Africa, The Civil War, the War of Independence would all be considered as positive wars by most Americans and all suffered atrocities committed by the "good guys".
What does it mean? Be firm in your committments. Be ready to fight for the ones that matter. But, be open to changed circumstances. and most of all be open to your fellow human beings, the earth, and any correspondence from beyond our limited plain of existence.