My view of Steve Jobs being mean comes from Walter Isaacson's biography. What would change my mind is if the witnesses mentioned in the biography came out claim

My view of Steve Jobs being mean comes from Walter Isaacson's biography. What would change my mind is if the witnesses mentioned in the biography came out claiming that the stories were fabricated. But if the stories are true, then he was a nasty person. That he may have been nice to some people does negate the nastiness to other people. My view of Zuckerberg being mean comes from personal experience. Zuck was not that mean, nothing like Walter Isaacson's description of Jobs. But at the time (years ago), he was probably 90th percentile in terms of meanness of the people I have known. He could sneak in barbs and be quite disdainful to people who he viewed as less than him (in one case shouting a person down and calling them stupid). In a previous comment, you wrote that "but it's a mistake to believe you know someone based on a collection of sensationalized stories." This is correct. But is there any evidence that the stories about Jobs or Bill Gates were sensationalized? "Sensationalized" is the operative word. If the stories are true, then the person is in fact mean, and it is a mistake to view them as not mean, simply because they are always nice around you.