Inspired by a 1940s short story by Harry Bates, scripted by Edmund H. North, and directed by Robert Wise, The Day the Earth Stood Still (1951) is a science fiction cult classic. Of all its diverse interpretations, a commonly adopted reading influenced by the dawning of the Atomic Age parades it as an anti-nuclear exemplar starring alien emissary Klaatu visiting Earth with his robot companion Gort to (supposedly) suppress humanity’s atomic progress. However, upon a close forensic inspection of the film and commentator comments, this anti-atomic claim is resoundingly rejected. Utilizing humanist film criticism as the guiding analytical lens (i.e., looking inside not outside the frame), plus a selective review of the critical literature, it was demonstrated that: (a) there is a dearth of atomic iconography and dialogue, (b) there is no mention of banning atomic energy or weapons, (c) Earth’s atomics are nascent and not serious threats to the Federation, and (d) Klaatu is not anti-atomic but proudly pro-atomic. Overall, this SF film is strongly pro-nuclear in intention, word, and deed, which was frequently misinterpreted due to faulty film criticism, invented facts, and jumping to conclusions, and thus in need of academic correction. Further research into alien first-contact scenarios, robotic artificial intelligence, and the moral make-up of the SF universe is warranted and long overdue.