I concur: adding fantasy quotes to serious subjects dilutes the seriousness and credibility of the topic.
The truth is the Truth no matter where you find it. I think back biting and nitpicking do far more toward diluting such threads.
Let me rewrite it:
John Doe: “Let me tell you something about people, Nephew. They’re a wonderful, friendly people, as long as their bellies are full and their tv’s are working. But take away their creature comforts, deprive them of food, sleep, hot showers, put their lives in jeopardy over an extended period of time and those same friendly, intelligent, wonderful people... will become as nasty and as violent as the most bloodthirsty gangbanger. You don’t believe me? Look at those faces. Look in their eyes.”
Maybe you can see what the meaning is now.
Fantasy?
Regardless of the source, it seems a pretty accurate take on human nature.
(You do know why there are no muslims in the Star Trek universe, don't you?)