Self-control is certainly required to win in business. Only stupid or mentally ill people would ever be overtly "mean" in a situation where they couldn't get away with it (Steve Jobs, Bill Gates, Linus, etc know they can get away with it)
Take for example the quality of empathy - It consists of 2 aspects :- 1.The intellectual ability to put oneself in others shoes. 2. Too feel emotional pity/sympathy when something bad happens to them. It is shown that empathy is a key aspect lacking in psychopaths. As PG points out - empathy helps us to navigate the social world. Hence, such people have difficulty handling social situations.
Steve Wozniak who is a genuinely nice person had a strong sense of empathy and was motivated by it to help others (eg:- giving significant portion of his own shares to someone who was shortchanged during Apple's IPO)
On the other hand Steve Jobs was what you would call a "highly functioning sociopath" - Someone who had strong emotional intelligence which could be used to great success in charming and manipulating people into doing one's bidding while at the same time, having an almost pathological inability to feel any sympathy for others or remorse for one's actions.(Take the same example where he refused to help out said employee or the time when he screwed over Woz). Unless I am mistaken, this aspect of Jobs's character is hinted at in Walter Isaac's biography of Steve. I believe this rare combination of both high emotional intelligence and cold ruthlessness was one of the key factors (among many others) in Steve Job's success. I don't want to over-exaggerate things or to imply that Jobs had absolutely no empathy (As a counter-example Jobs clearly loved his adoptive parents and felt great remorse over a relatively minor incident mentioned in the book) but he does seem to be an unusually mean person (much more than Bill Gate IMO).
You may not like how the man presents himself, but that is just flat out unfair.