I think it has a lot to do with expectations and how they need to change in light of such an event.

In 2017 there were no commercial passenger jet deaths - that's how amazingly safe these machines are. Any such crash casts doubt on this idea.

Imagine the difference between "literally perfectly safe" and "can (rarely) cause death".

Same with events like 9/11 - no one going to work that day expected to die like this just hours later.

Pneumonia has a death rate of up to 10% among hospitalized patients(mostly older folks), so people who drop off their parent at the hospital are often already mentally preparing for the worst.