Because a discussion of such an article is going to be almost pure politics, and almost certain to degenerate into a flamewar. That's not a good/worthwhile/useful discussion. (There's other places to do that; we don't need to do it on HN.)
I respect HN's ability to have decent discussions. It's better than anywhere else I know of online. But I'm pretty sure that this one would degenerate, quickly and irreparably.
Or, more accurately, there's nothing to be discussed but the superficial.
It seems unfortunate to ghost the article simply in anticipation of a poor discussion. Other contentious topics have been discussed on HN, and I for one would appreciate an objective HN-style discussion of the information presented