Re: Why Krishna did not participate in M.B war?
The answer to your question is there in your own post.
As you said, the important thing is to create accountability for our own actions.
My own input here is that Krishna was an Avatar, and an Avatar comes once in a while and is not a regular actor in this world of ours. As Krishna says in the Gita, ' There is nothing in this world as purifying as knowledge.'
If Krishna fought with arms in the Mahabharatha, the Gita would not have been created or recorded. This is because even if Arjuna left the war, Krishna would have fought and singlehandedly won the battle for the Pandavas.
But that would not serve the purpose of the Avatar. Krishna and Arjuna were the sages Narayana and Nara in their past life, who performed great austerities to perform their latter roles.
The Bhagavad Gita, which has inspired millions of people to attain enlightenment or lead righteous lives, came out of the Mahabharatha war. Krishna ensured that the knowledge of the Gita came into being so as to inspire people to be yogis and righteous in the coming Kali Yuga with the proper perspective and wisdom.
It can be compared to a mother teaching her child to walk. If the mother held her child always when walking, he would not be able to walk properly. She has to let go and not allow the child to depend on her superior strength always while walking so that he can be self-reliant and start walking on her own.
Similarly Krishna wants humanity to be strong and wise through its own efforts and not by depending on the presence of the Avatar at all times, dependence which would cripple its own intrinsic strength.
In every moment you only have one real choice: to be self-aware or to identify with the body and the mind. -- Annamalai Swami
Body-consciousness is the source of all misery. -- Ramana Maharshi