"Demonic possession"? That is really sad. Your response was perfect AND certainly in words he could understand. 
Way back when I was in my twenties, I used the word "basically" and the guy I was talking to thought I was being stuck up and accused me of being college educated. I was speechless that time, I didn't know how much more simplistic I could speak.
My daughter is really good at comebacks, usually short and to the point. When it comes to uninformed right-wingers, she is more inclined to ask a question which throws them off script. Just a simple, "Really? Where did you hear that?" can be very effective. She was really upset when she found out her beloved uncle had bought into all the right-wing media propaganda and she managed to really turn him around in a relatively short period of time. Hopefully it stuck. They can relapsed so quickly.
The "property damage" reference was saying that I wouldn't resort to their vulgar language, much like I wouldn't damage their property. I was tired and wasn't being very clear.
We live in such surreal times. It is often hard to take it all in. I have been around all kinds of people throughout my life and I've never seen anything like what we've witnessed in recent years. I can remember when political debate could be stimulating and civil, even fun sometimes. No one thought twice about putting a bumper sticker on their car or sign in their yard. I can't imagine what my father, a republican precinct captain, would think of a sign or pin that said Fu*K the opposing candidate.
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