It's not called sensitive when someone gets pissed when you're making fun of death
Making a joke about a tragedy doesn't mean they're insulting everyone involved or saying it wasn't a tragedy, nor does it always mean they're making fun of death.
Those who take all dark humor personally and pick a fight are creating conflict for the sole purpose of creating conflict. On that note, dark humor can still be tasteless or offensive. It all relies on intent and execution.
Although it's unfair to say you can't joke about anything bad that happened just because it
MIGHT make somebody offended. There's always going to be somebody that's offended by a joke. That doesn't make a joke offensive.