Rationality, control, intelligence.
They will defeat passion any day of the week.
Fans always like and defend "passionate" owners because the fan feels like they are one of them. The fan jumps around passionately being an idiot, and look so does the owner, so ahh, a soulmate (some people vote the same way, to similarly shaky results). But you don't want a soulmate in your leader, your decisionmaker. You need that leader to be rational, smart, in control, a strategist. You need to be able to count on them to make decisions for the right reasons, not because of "passion". "Passion" gets you **** trades to dump franchise players. It gets you fired coaches. It gets you kneejerk moves without plan or focus. That's NOT what you want out of a leader. Any leader. Be it coach, GM, or owner.