“Unreasonably dark joke,” read a coronavirus meme circulating on social media in recent weeks. “Shouldn’t we wait until after the pandemic to fill out the census?”The joke is dark, yes. But is it any darker than countless other coronavirus memes out there?Even more pointed is a spoof movie poster for “Weekend at Bernie’s,” the 1989 film comedy about two buddies toting around a dead man on their partying adventures, called “Weekend at Boris.” It cast as the corpse Boris Johnson, the British prime minister, who at that point was still in intensive care for Covid-19, as the corpse.Since the pandemic took hold, the internet has been awash with coronavirus-centric joke memes, Twitter wisecracks and self-produced comedy sketches shot with smartphones in shelter-in-place kitchens and living rooms. And that’s not counting what’s happening in private conversations during quarantine.Laughing while others die may seem inappropriate, even tasteless, like concentration camp prisoners cracking jokes during the Holocaust. But in fact many did, according to a 2017 documentary, “The Last Laugh.”Throughout history, humor has played a role in the darkest times, as a psychological salve and shared release. Large swaths of the population are living in isolation, instructed to eye with suspicion any stranger who wanders within six feet. And coronavirus jokes have become a form of contagion themselves, providing a remaining thread to the outside world for the isolated — and perhaps to sanity itself.But who, or what, is an appropriate target for satire during a pandemic?You can’t laugh at the sick or dying, obviously, except in the main. “A year from now, you’ll all be laughing about this virus,” reads one recent meme. “Not all of you, obviously.”The virus itself deserves scorn and mockery, being the source of all this misery, although it is an elusive target, being inanimate and invisible. (“I love being outdoors, crowded places and food markets,” read a fake Tinder profile for “Coronavirus, 29.”)As late-night hosts like Seth Meyers and Trevor Noah have shown, politicians who seem to prioritize votes over lives are easily mocked. So too are other perceived villains of the pandemic that require no microscope to see: six-foot-space-cushion violators, say, or toilet-paper hoarders.“What’s next?” Mr. Noah joked in a segment a few weeks ago about people getting into fistfights at supermarkets over jumbo packs of Charmin. “Are people going to be running around Walmart, like, ‘Ahhh, where’s the car wax?’”Judas on ZoomIn many ways, we are all our own best source of humor, racked with anxiety as we sit cloistered at home, surrounded by either too few people or too many. With little contact with the outside world beyond our smartphones, our jokey coronavirus memes and videos are like the S.O.S. messages that a bearded castaway fashions in the sand with rocks and seashells. More