Grasshopper...You cannot reason with...
Communists, Neocons, religious fanatics or racists.
But you can let them post away and make fools of themselves and to discredit their own cause by their unpleasant behavior. True, effective, propagandists do not attempt to win arguments, they seek to plant a seed of doubt instead. The trick is to be subtle and invisible, not forceful and domineering. And the most effective propaganda of all is to simply let your opponent step on his own dick, while you politely look the other way, smiling.