I guess you and the professor live in the same idealistic, perfect, and flawless suburb, where the sun shines even at night. But the world spans beyond your happy gated hippy community and it's a cruel place.
First and foremost consider who you're up against. All those lovely people in Russia, China, NK, ..., are kept at bay precisely because they know why US ICMBs are named "Minuteman." If you put a speed bump in the way of retaliation, you'll only embolden them. Fighting against an impotent, incapable, and snared opposition is anyone's dream. Why do you think China so casually runs concentration camps today, right now? And Russia so casually annexed territory of a foreign country - which, btw, handed over their nukes to Russia in exchange for protection.
"Ignoring the fact that the value of the use of atomic bombs against Japan is heavily debated to this day..."
The dimensions of the planet is also heavily debated, but that doesn't change the facts of it. The two nukes ended the war then and there, Japan capitulated without a single soldier setting foot on the mainland. Only someone to whom empathy is an alien concept and completely out of his mind can argue that invasion would have been better. If you have the imagination, picture yourself in a boat en route to certain death, you and millions like you, having to fight for every strand of grass against an enemy that considers their (unseen) emperor a god for which they will gladly die for, because it's honorable.