News stories buried after their shelf lives expire, or never had national appeal until a documentary filmmaker decided they did, present false dilemmas. As viewers, we tell ourselves we want to know enough of what happened to sell us on committing eight hours of sparse free time, but not so much that a major reveal is spoiled or actually watching feels redundant. Finding balance in that Goldilocks zone seems like a pointless and futile exercise: we’ll exceed our arbitrary limit of allowable information almost inevitably by virtue of reading even the most bare-bones Wikipedia page or watching a trailer. And truthfully, who cares? The Jinx is still exciting even when we know Robert Durst’s slipped confession of killing all those people is imminent. We watched Wild, Wild Country to hear how a cult wound up committing the largest act of bioterrorism in American history. Evil Genius sounded insane exactly because the conclusion was dangled as bait, but even the "big get" in the final episode felt more like a gentle confirmation of things we already presumed rather than an "a-ha" moment.
The Staircase is especially unspoilable, presuming access to the necessary resources: you had 14 years to track it down, the case itself has been widely covered for nearly 20 years, and "the staircase killer" has practically become a TV trope for crime shows. But the series' mastery of structure and pacing, plus the depth and oddity of its characters, shield it from distillation into a handful of episodic talking points. The lack of clear answers leaves it room to explore the absurd -- like a legitimately presented courtroom theory of death by owl -- and still demand you take it seriously, because compelling true-crime shows explore so much more territory than "whodunnit." Nonfiction's worthwhile unknowns are the connective fiber that give life and movement to the established facts of any story, and God forbid any of us have friends pedantic enough to memorize and regurgitate every single beat they saw in an eight-part documentary. Even a meticulous review can't strip away the firsthand experience of watching a well-crafted show or film, true life or not, and coming away with our own theories and assumptions about who we want to believe.
Ultimately, consider your audience. Everyone has their own tolerance quirks, and all you really have to do is ask if someone cares about spoilers, even if the thing at hand can't really be spoiled. If a person you care about genuinely wants to hear nothing, courteously roll your eyes at them but respect their wishes, stubborn and misplaced as their paranoia may be. True crime's allure doesn't rest in splashy reveals or meticulous action sequences. Compelling us to gawk at the darkest corners of humanity, in spite of knowing exactly how it's going to end, is reason enough to watch.