Schadenfreude to the extent of humour. That is a difficulty isn't it, the audience can find whatever it wants funny if that's how it's wired. Perhaps you're right.
It's definitely contextual. As an example, military or veterans, first responders, doctors, lawyers, and others like that will usually have a much greater appreciation for dark humor than people who haven't had to deal with tragic circumstances in their day jobs.
I don't think that necessarily follows. Some infinities are greater than others.
(Even though I happen to think anything could be funny with sufficient effort. Even tragedy)