The right number is zero and a UBI until they figure out how to stop being jerks. (My primary personal reason for supporting a UBI is I want to be able to say "No rational employer should employ you" without that implying "so you should be homeless and starve.")
But short of that, the right number is zero on the interview circuit. You can employ jerks if you have to, but don't put them in more positions where they have to interact with others than necessary. Give them the legacy products where you can't staff a team of more than one qualified person anyway. Give them an office. And keep the door closed.
Remember that a jerk is basically a 0.1x developer - an employee who causes other employees to lose productivity by spending time working around the jerkiness, taking a morale hit, etc. Even a remarkably productive jerk at best only compensates for their negative effect on people they work with, and most jerks are not consistently remarkably productive. https://medium.freecodecamp.org/we-fired-our-top-talent-best... is a good example of a company learning that lesson a little too late. A company that signals that they trust their jerks enough to make hiring decisions and to represent the company's culture to potential new hires is a company that signals they're actively cool with jerks (or incapable of noticing, which has the same effect).
If a jerk makes a good employee unhappy and they leave, the jerk is a net negative. And if you keep employing the jerks, you'll find yourself with a 0.5 jerk coefficient on your hands very quickly.
Just hiding how many jerks a company has until after the interview process is complete is not effectively any better - it could even be worse for people, as they could have had signal to avoid the jerk. The absence of evidence of some behavior or signal is not equivalent to it not being present at all.
In my experience, most companies have jerks - I’m not convinced it’s even avoidable reliably, as people come from many walks of life, and sometimes the walks form people to be jerks.
I work at Apple, where I’d say that jerks are a very low number of people I’ve interacted with (maybe a couple hundred employees so far) - I’ve seldom seen a company beforehand with less jerks percentage-wise, much less have processes that help with descalating arguments & deal with them quickly.
But short of that, the right number is zero on the interview circuit. You can employ jerks if you have to, but don't put them in more positions where they have to interact with others than necessary. Give them the legacy products where you can't staff a team of more than one qualified person anyway. Give them an office. And keep the door closed.
Remember that a jerk is basically a 0.1x developer - an employee who causes other employees to lose productivity by spending time working around the jerkiness, taking a morale hit, etc. Even a remarkably productive jerk at best only compensates for their negative effect on people they work with, and most jerks are not consistently remarkably productive. https://medium.freecodecamp.org/we-fired-our-top-talent-best... is a good example of a company learning that lesson a little too late. A company that signals that they trust their jerks enough to make hiring decisions and to represent the company's culture to potential new hires is a company that signals they're actively cool with jerks (or incapable of noticing, which has the same effect).
If a jerk makes a good employee unhappy and they leave, the jerk is a net negative. And if you keep employing the jerks, you'll find yourself with a 0.5 jerk coefficient on your hands very quickly.