A lot of the population consider intelligence to be the most crucial thing that someone should have in order to lead. Intelligence does not only consist of academic knowledge, but also social and even physical ones. A leader that has none of those will not be able to bear the tasks that they must fulfill, that is exactly the reason why i agree with this statement.
Many of my fellow laypersons believe that intelligence only consists of knowledge that you learn from books, schools, and courses. That kind of belief could be the reason why people are refusing to consider it as the most essential thing in leadership. Even when that is not the reason, the other options that they think are more necessary are relations and personal branding, which while I think are important, are not as important as intelligence.
There are multiple classifications of intelligence, from academic, logical (which in turn is quite intertwined with academic) down to social, visual, or even audio. All of these are important for us to have when leading our comrades. For example, when there is a heated debate between our members, we as a leader must be able to calm them down using our interaction skill and try to rationalize it for them, so that we could get the desired outcome. Or when we are travelling around the forest and badly need some in a freezing night, by using our knowledge and logic, we could create a fire for the crew to keep us warm at the time being.
To summarise what I have written, there are multiple opinions on this subject, whether because of preferences and/or views. But, I still stand firm with the opinion that intelligence is the most necessary quality that we must have when we hold the responsibilities of a leader.