I'm going to assume that if it was representative of the 5%, it was of the 1% of that 5% who chose to position their thoughts in an eloquent and respectful manner.
His reply is also an example of a positive, thoughtful, and respectful response to another's position. The letter was fruitful in that gave him much to espouse upon in his reply.
In this way, it may just have been the perfect example for his community outreach. And I'd say it was an excellent choice.
I think his point is that the letters are coming from the 5%, where there's a silent majority. There's a silent majority that is probably frustrated by protests on the interstate, but arresting people for the "die ins"? I think most people agree that those protests are well within the freedom of assembly.
Not many people write in to feel they are moderately satisfied with the way things are going, I would think.