I'd recommend everyone read up on "blood diamonds" or "conflict diamonds" as well as the diamond market in general before ever purchasing a diamond for jewelry.
Why is it so inaccurate? "Coltan is a metal that conducts heat unusually brilliantly." compare to wikipedia: "Coltan is the colloquial African name for columbite - tantalite, a metallic ore from which the elements niobium and tantalum are extracted." Also in wikipedia: "The United States Geological Survey reports in its 2006 yearbook that the Democratic Republic of the Congo produces a little less than 1% of the world's tantalum." - so this implying of guilt for everyone buying electronics is rather silly.
He trades truth for rhetorics undermining all the sympathy I might have.
I'm guessing most hackers aren't diamond buyers. I recommend everyone read this before buying any computers or electronic gadgets: http://www.johannhari.com/archive/article.php?id=863