I have dealt a lot with these types of late and have a few observations.
1. Approach slowly and talk softly. They are not long on courage and hate being confronted.
2. Don’t refer to absolutes. There are none in FLAAPL – World. There are no rules and if you do agree to any they will be changed or ignored when they get in the way of feelings.
3. Never use facts. Facts confuse FLAAPL’s. You would be better served to restrict yourself to feelings. Feelings no matter how irrational and lacking basis in fact are given far more weight and credence than facts. In fact facts, seem to confuse FLAAPL’s. If you use more than 2 in a 10 minute conversation FLAAPL’s tend to start to turn color and there have even been reports of spontaneous FLAAPL combustion.
4. Don’t use God in a conversation. In FLAAPL-World everything and everyone is a god – hence no moral absolutes, everything is relative to whoever your god is.
Now that you have a few suggestions never take a FLAAPL for granted and never plan on winning a debate with them as soon as things start to go in your favor they will change topic and start to attack your character. Again be warned there are no rules in FLAAPL world so whatever assertion they make will not be based in fact {see rule 3} in fact it will not be based on anything so as to make it impossible for you to refute them.
Remember the American Constitution guarantees their rights even while they are trying to take ours away.