I think that I do have a "moral obligation" as a human being. As a human being I have an obligation to be a productive person. My motivator is my own happiness. I do not believe that anyone else can lay claim to my life. My obligation to be productive stems from what it means to be a human being, not from any duty to others. I study aikido in order to better be able to protect my right to pursue my own happiness. If I thought that my study of aikido made me responsible for the actions of every thug on the street, or for the safety of others, then I would quit today.
May I ask what it is about being an aikidoka that makes one morally responsible for the safety of others?