This is a very sensible and well-reasoned, if ridiculously windy[1], essay which has its basis in one completely erroneous assumption, which is that it's possible to answer, save after the fact, a question like "[A]re we morally developed enough as a species to be entrusted with nuclear weapons?"
That's a very simple question to answer, but you can only do so in hindsight. Did we exterminate ourselves with nuclear weapons? If we did, then we weren't morally developed enough to be entrusted with them; if we didn't, then we were.
And even in that, there's another bogus assumption, which is hidden behind the word "entrusted". No one entrusted the human species with nuclear weapons; there was no event in which God, or angels, or sufficiently advanced aliens, descended from on high, amidst clouds of incense or rocket exhaust, and bequeathed unto us the knowledge of what happens when you squeeze a ball of uranium very tightly. It may seem absurd to point this out, but only until you consider that "entrusted", in implying a higher power which did the entrusting, implies also a higher power which could reverse that decision; there being no such power, it is impossible to reason accurately about the morality of any technological development when such reasoning involves the implicit assumption that there is such a power.
[1] Those familiar with my comments on HN may be astonished to see me calling anything "windy", much less ridiculously so. In my defense I can only say that I reserve the use of that adjective and its adverb for cases of extreme provocation, the nature of which should be obvious to anyone attempting to wade through the text I've so described.