Almost no one these days regards axiom compiling as a way of describing emotional phenomenon, such as altruism. The idea of describing such warm reasons in terms of axioms was so unintuitive that it caused your friend to think that you were looking for some other reason for social justice, other than a basic appeal to better human nature. He may have been disgusted at what he thought was an implicit disregard for the more altruistic reasons for social justice, as if they weren't themselves sufficient to do good things.