|Flickr user BadSwan|
Some people are like that missing stair.
When I posted about a rapist in a community I belonged to, although I gave almost no details about the guy except "he's a rapist," I immediately got several emails from other members of that community saying "oh, you must mean X." Everyone knew who he was! Tons of people, including several in the leadership, instantly knew who I meant. The reaction wasn't "there's a rapist among us!?!" but "oh hey, I bet you're talking about our local rapist." Several of them expressed regret that I hadn't been warned about him beforehand, because they tried to discreetly tell new people about this guy. Others talked about how they tried to make sure there was someone keeping an eye on him at parties, because he was fine so long as someone remembered to assign him a Rape Babysitter.
People had gotten so used to working around this guy, to accommodating his "special requirements," that they didn't feel like there was an urgent problem in their community. They did eventually expel him, but it was after months of it being widely shared knowledge that he was a rapist and had done other unethical sexual things as well.
I think there were some people in the community who were intentionally protecting him, but there were more who were de facto protecting him by treating him like a missing stair. Like something you're so used to working around, you never stop to ask "what if we actually fixed this?" Eventually you take it for granted that working around this guy is just a fact of life, and if he hurts someone, that's the fault of whoever didn't apply the workarounds correctly.
"Fixing" doesn't always mean throwing someone out. (Although in the case of sex groups I think people are way too timid about that. Being invited to sex parties should be a positive show of confidence in your character, not some sort of default human right.) Sometimes a person can be "fixed" by talking with them bluntly about their behavior, giving them specific rules to follow, or putting them on notice that they have one strike left. You don't always have to get rid of "missing stair" people, but you do have to work with the person, not around them.
This isn't just about sex. Just about every workplace has that one person who doesn't do their job, but everyone's grown accustomed to picking up their slack. A lot of social groups and families have that one person. The person whose tip you quietly add a couple bucks to. (Maybe more than a couple, after how they talked to the server.) The person you don't bother arguing with when they get off on one of their rants. The person you try really, really hard not to make angry, because they're perfectly nice so long as no one makes them angry.
I know not all these people can be fixed, and sometimes they can't be escaped either. But the least you can do is recognize them, and that they are the problem. Stop thinking that your inability to accomodate them is the problem.
This isn't just about individuals, either. Everyone who says "I don't want to be a victim-blamer, but girls should know frat parties aren't safe places" is treating rape culture like a missing stair. Everyone who says "it's an ugly fact, but only women who don't make trouble make it in this business" is treating sexual harassment like a missing stair. Everyone who says "I don't like it either, but that's the way things are," and makes no move to question the way things are, is jumping over a missing stair somewhere.
Fixing staircases is a long and difficult and uncertain process. But let's at least stop blaming each other for not jumping well enough.