"Gladys Owens, the woman seated in the foreground, did not know what she had been involved with until seeing this photo in a public tour of the facility fifty years later."
The first proof that this was not in fact the case came in the Frisch-Peierls memorandum (https://en.wikipedia.org/wiki/Frisch%E2%80%93Peierls_memoran...), which had been written two months before Harrington's article appeared, but which was highly classified and thus out of reach of pop-science journalists. Frisch and Peierls' figures indicated that a critical mass could be achieved with just one kilogram of uranium-235; this turned out to be an underestimate, but not so much as to invalidate their fundamental point, which was that criticality could be achieved with a mass of fuel small enough to be delivered by a 1940s-era airplane.
This came as news to the brightest lights in the world of physics, up to and including Albert Einstein, so it's probably unfair to expect a contemporary writer for Scientific American to be further ahead in the science than they were.
But perhaps most amazing are these results from physics experiments in 1940 and then the changes in the world by 1945. Such profound changes are also likely when someone figures out how to tap the energy from fusion as well.
"When a distinguished but elderly scientist states that something is possible, he is almost certainly right. When he states that something is impossible, he is very probably wrong."
The relevant question however was "Can the setup be engineered that it could be made to happen" and the answer to that with all that was known and elaborated in the article was: "Maybe if a larger percentage could be made slower or absorbed by other means".
Answering the wrong question is a common way to misdirect.
So basically, clickbait through the ages.
Thus the reaction poohs out as the temperature rises.
And what's critical mass? Some form of feedback system (a 'strange loop')?
What's the equivalent of enriched uranium for healthcare?
What's the equivalent of enriched uranium for calculus?
What's the equivalent of enriched uranium for sweatshirts?
As for 'critical mass', a defining characteristic of consciousness is that it's self-referential, so that seems like a fair guess.