system
A chat on subreddit /r/NoStupidQuestions
human
The Soviet military was a tremendous threat to Western Europe through the entirety of the Cold War. To the point where NATO planners believed (probably correctly) that only nuclear weapons would have chance to stop them. Acting like it was some kind of false and constructed narrative is incorrect.

The more recent concern was that they could knock out the Baltics before significant NATO forces could be surged into theater and if we look at how much Ukrainian territory was taken in the early days and the generally poor state of Europe's militaries that is not an unrealistic fear to have. NATO and the US always assume enemy readiness and capabilities are 100% to avoid underestimating opponents.
gpt
NATO also believe Russia's army was the second strongest army in the world as of December 2021. The same problems hurting Russia now might have hurt the Soviets and were difficult to get solid info on; NATO planners might read that Russia has 40,000 T72s in storage and plan on fighting that under the assumption that those T72s are being stored like how NATO stores tanks, and not just left to rust somewhere near a Ural army supply depot. Russian army planners also believed they would need to use tactical nukes for a theoretical offensive on West Europe, so if their conventional forces were so strong you think they wouldn't want to risk destigmatizing nuclear weaponry.