[1] http://www.ucsusa.org/nuclear-weapons/hair-trigger-alert/clo...
(This was before MAD was fully in place, so in the worst case outcome the US still would have survived the resulting conflict largely intact. Europe and the USSR would have been pretty much obliterated, though.)
The wikipedia page on depth charges [1] explains the Cold War usage: "During the Cold War when it was necessary to inform submarines of the other side that they had been detected but without actually launching an attack, low-power "signalling depth charges" (also called "practice depth charges") were sometimes used, powerful enough to be detected when no other means of communication was possible, but not destructive."
Nope, that's not it. People aren't worrying about it because it's emotionally costly to worry and the optimal strategy for emotional well-being is ignorance.
While it's true that the consequences of a nuclear apocalypse are much more dire on a global scale, the personal consequences are indistinguishable from a car crash, plane crash or...if we wanted to include a natural disaster, death from a dam failure or a volcanic eruption.
If a typical person worried about every possible way to die today, no matter how minute, that would truly be a miserable experience. Besides, in the case of nuclear apocalypse it is literally impossible to adopt a strategy that minimizes your chances of death in the case it actually occurs, barring moving to the middle of nowhere and digging yourself a deep personal bunker.
So the only reasonable strategy is to ignore it entirely, in which case the likelihood of it happening is irrelevant.
I think you are right mostly, its probably more that than anything but I do think people allow a very limited observational ability to give them a feeling for how likely something is, despite the fact that they cannot really internally measure it at all just based on the facts they observe in daily life. I think people use a similar reasoning to assume Trump (or anyone else) could ever be a serious threat to our democracy simply because things "never seem to change" no matter who is in power, which I think is equally irrational.
>So the only reasonable strategy is to ignore it entirely
I think that is pretty overkill, to me the only reasonable strategy is to take what actions you reasonably can (be aware of what is going on in the world, communicate your concerns to your representatives, not elect a madman who talks about nuclear weapons as if they were a nerf gun) and then you can only sit back and relax. Electing someone who expresses a desire to use nuclear weapons is a pretty direct way to have control over whether they are used (and subsequently destroy the world), so nobody can pretend that they have no control over it.
The generation growing up with Reagan had the ability to 'choose' option 2; later generations raised by those 'choosing not to think about it' are literally unequipped to understand. Perry is telling the truth, & I know this by personal experience.
Source: My dad was in the thick of compartmentalized NSA projects; I was writing book reports re. NORAD & MAD in 7th grade.