Yes, that's right. We do define ourselves in every waking moment but the purpose of discussion is not self-definition but rather the establishment of a mutually-satisfactory description of the world we see around us and of worlds we can't see (the historical for instance). In order to arrive at that description, we need to 1) define terms (something which many of us here have attempted to do with "field grade"), 2) find an ascending set of premises upon which we do agree (something which has proven difficult particularly in relation to the "means test" as an indirect indicator of who might be expected to buy a certain gun at a certain price in a certain year), 3) treat propositions as stone-cold hypotheses to be provided with evidenciary support or abandoned, 4) avoid the argumentum ad hominem in even its most subtle forms such as the skull-sucking presumption that your friend's arguments are made invalid by a misanthopy so virulent that he hates damn near the entire human race, inclusive of the inhabitants of Hardscrabble AND the lumpen middle class. [And sometimes it just pays to lull em to sleep with "my bad" and "I see your point" while sticking your lever in elsewhere.]
jack
