The "fly bite" thing is something I say when the opponent of debate has resorted to the tactics you describe
or refuses to follow or recognize logic in the debate. Often when the opponent has presorted to statements like "Are there really people like you," "How can you believe something like that," "you present no proof at all, just ignorance," "You show your ignorance," "You must be out of your mind,""Do you always attack a person" etc.
Often the opponent of debate who can not win the argument with correct logic, resorts to name calling and attempts to make the opponent feel guilty for the antagonist's failures. Most people on this forum have resorted to sarcasm to prove a point or to quite the discussion. "Are you one of those people" is a good example of how to put down an opponent before he has had a chance to say anything about the argument. The GadFly uses the fly bite thing to tell the antagonist he is responding out of anger and not common sense or logic. It is relatively effective but it seems to generate more hostility than needed towards the GadFly. For that reason, you will probably see far less use of the fly bite thing but at he same time, the GadFly thinks it is also humors the way it reflects what is really wrong with opponents. So,let me say this: see you when it is time for the next bite ..... just joking.
GadFly