I haven't read the Smithsonian article yet, but from what you wrote, I'd say it's a shame Morris apparently decided to go for sensationalism instead of the facts.

Sensationalism may sell, but so too do books that are dedicated to fact.  Moreover, books like Fatal Justice, and articles like the one Morris apparently wrote, often tend to fade away, while more factual accounts stay around and often become classics.  Witness In Cold Blood, Helter Skelter, Small Sacrifices, and many more.

Too bad for Morris that he chose to present the case in the way he did.  In my opinion, it may result in a loss of credibility from which he may not recover.