It is a sound philosophy. Every individual dislikes and naturally reacts negatively to threats of violence or the use of violence. If we take that personal understanding, and realize that everyone else has that same natural negative reaction, we have universalized the non-aggression principal. This is what needs to happen in society for us to reach a voluntaryist society.

We each dislike threats of violence and the use of violence upon us, the real difference is do we extend that to others (voluntaryism) or do we NOT extend that to others (moral relativism) ?