It mentions those with "dark traits" tend to be seen as poor team players, but perhaps that's exactly why these types ascend to top leadership positions. Your "team play" ability only matters to the extent that you engage in peer-to-peer relationships, which can be relatively minimal in that position compared to, say, middle management. See, for instance, Steve Jobs. I've never heard him described as a "team player",…
It doesn't "only matter" in relationships that are horizontal on the org chart. They're just not the totality of the non-peer relationships. Understanding and communicating boundaries between teaming and exercising authority is key to efficiently moving everyone toward a target.
To torture the sports team metaphor more, the captains on a team are players but also an authority among the players. To the front office, a coach is a member of the gameday team.