Evgeny Morozov once dismissed a book by Jeff Jarvis with the acerbic one-liner, "This is a book that should have stayed a tweet." Neil deGrasse Tyson hasn't written a book, merely a Facebook post, but still, the same principle applies; he should have just left things well enough alone.
What I find most interesting is that Tyson helpfully links to several critical articles written in response to his original tweet, from which he apparently learned nothing. Like Mr. Magoo blithely traipsing across the yawning chasm of the is/ought divide, he somehow manages to arrive at the proposition — offered, as far as I can tell, in all seriousness — that in his utopian state of Rationalia, we might create an "Office of Morality" (because "Ministry of Truth" was apparently already trademarked) where moral codes can be debated and settled. Perhaps these new morals can be enforced by an equally-innocuous-sounding agency, like, say, the Committee of Public Safety, or some such. Had Tyson bothered to study the, uh, evidence accumulated thus far, he might have realized that Brian Carnell's vision of the glorious future much more closely resembles what we've learned from empirical observation.