hane had this notion about guns, “A gun is a tool. No better and no worse than any other tool - an axe, a shovel, or anything. A gun is as good or as bad as the man using it.” What is the interpretation of this?

I think there is a double meaning here. There is the skill part of how good a gun is related to the man (the man using it). The statement also relates to the morality of the gun being shot. It is the person who decides if it a worty cause or not.