One other difference - at least in terms of perception - is that the threats you listed are relatively static over time. Terrorism is a movement that involves recruitment and contains inherent plans to expand.
To be the first to invoke Godwin's here, the Nazis did not statistically represent a significant daily threat to health and safety in 1928, either. Looking at present body counts as a gauge for what's worth "freaking out" about seems incomplete.
Exactly, terrorism is a high-variance event and we can't extrapolate that future violence will resemble current violence. A single catastrophic attack, like a nuke in a city, makes everything that happened before irrelevant. 9/11 itself was a huge escalation, the most deadly terrorist attack in history by far. Future death tolls are limited only by the capabilities of the terrorists and our ability to stop them. They would kill millions of us if they could.
> Future death tolls are limited only by the capabilities of the terrorists and our ability to stop them. They would kill millions of us if they could
This is rather sensationalist. There are infinite ways that anyone with a bit of intelligence could hurt or kill large numbers of people with small arms, explosives, chemicals, vehicles etc - and yet we see time and time again that terrorists usually display extreme incompetence (e.g. underpants bomber). The few terrorists that there are, just aren't very good at it.
The idea of terrorists getting hold of a nuke and actually being able to use it effectively is, frankly, ridiculous.
It's unlikely that a nuke falls into terrorist hands, but its not unimaginable. Pakistan is a half-failed state with nuclear weapons and it's easy to imagine that government collapsing completely. North Korea is another unpredictable actor. US officials have warned about lax security around smaller nuclear weapons in Russia. You are right that they would face further obstacles in trying to detonate it.
There are many more-likely but still catastrophic scenarios. A bigger Paris/Mumbai-style attack could kill thousands. An attack on the Hoover Dam or a chemical plant could also kill thousands and cause billions of dollars of economic damage.
I'm not saying we should be entirely complacent, but the response from the western world since 9/11, and ongoing, has been insane, and has caused more civilian deaths than any terrorist attack could ever cause.
Devices like this, or indeed body scanners, just add to the security theatre that makes corporations money and allows our politicians to further continue the narrative of fear that allows them to get away with almost anything.
To be the first to invoke Godwin's here, the Nazis did not statistically represent a significant daily threat to health and safety in 1928, either. Looking at present body counts as a gauge for what's worth "freaking out" about seems incomplete.