Business, at least as it is taught in our business schools and most training programs, is about understanding and knowledge.
These are, of course, both very important. However, managing is a skill, and (as it transpires) has nothing to do with rationality, logic, IQ, or intelligence. Whether you can manage is a simple question of whether or not you can influence individuals or organizations to accomplish something. It’s about influencing people, singly, in groups, or in hordes.
No amount of understanding, knowledge or intelligence will help if you are not able to interact with people and get the response you desire. I know a lot about management from my education. That doesn’t necessarily mean I’m any good at doing it.