Email from a man who got beaten up for reading my book

Hello Mr. Dershowitz.. This is not a question but a comment, I bought your book from Amazon titled "THE CASE FOR LIBERALISM IN AN AGE OF EXTREMISM OR WHY I LEFT THE LEFT AND CAN'T JOIN THE RIGHT.  My first comment is that I find it very easy reading and easy for me to understand. The other thing that I would  like to mention to you is something that I've never ever experienced in my entire life. I was reading your book yesterday at the beach, when some guys who I was playing beach volleyball with, asked me about the book that I was reading, and so I showed them the book. They then asked me why I chose this book, and so I told them that I had a great deal of respect for the author. The next thing that happened came as a total shock to me. Without warning, I was slugged and punched in the face. I asked why was that called for, and I was told that it's because his political view point and mine differ. I told them that I get it that our view points differ, but why can't we be at least civil about it. With that, he laughed, shoved me once again onto the sand, and kicked sand all over me.

My question to you is why people can have political differences, respect the others point of view, and just be civil about it? Honest to goodness, this is the very first time that I've ever experienced such an incident, and I would appreciate if you can tell me what I did to deserve this, because honestly I just don't get it. I was taught by my step mom to always be respectful of others, even though I may not agree with the other person. I thought that I was being myself and honest. I don't know, Mr. Dershowitz. I just don't get it on why I got and deserve this kind of treatment.

Thank you kindly, Mr. Dershowitz, and I look forward to hearing from you, so that I can understand better.