Name-calling is the oldest trick in the book. It's a trick used by people who lack the ability to explain their point convincingly. It is also a diversion tactic because it draws the arguments away from the main idea. Plus, it is nothing more than an attack on the messenger instead of the message.
In public forums, debates have this tendency to escalate into pissing contests once someone resorts to name-calling. Calling your opponent stupid, an idiot or a moron is a sign that you are getting frustrated. Frustration in public forums is easy enough to detect when people start using name-calling. Those who use this tactic do not seem to realize that they are the ones who look like morons.
Before you call someone a moron, you need proof that he is. Ask yourself the following questions:
1. Did your opponent hurt/offend himself or other people as a result of what he said.
2. Did your opponent waste resources/time/money?
3. Did your opponent say something that is libelous?
If the answer to all of the above is no, then your opponent is not a moron. If the answer to any of the questions is yes, then he is a moron.