3) Understand the Whole Picture.
When someone starts a post with “I can’t understand how anyone…” they are admitting that they have not tried to understand the other side of the argument. Go to the source, and find intelligent people who disagree with you. Stating that you are incapable of understanding other viewpoints is a statement about your ignorance, not your opponent’s stupidity. When you see a Facebook friend revel in their ignorance, does it change your perception of them?