Because of their multiple talents, they have something to contribute to the group and achievement of the goal. By joining the group, the members tacitly agree that they will stay focused on the goal and not do something to subvert the effort. When a member of the group does something that goes against the grain of the group's goal, it can be forgiven on the first time as a mere oversight or mistake. However, when the acts that are anti-goal achieving and detrimental to the group's achievement of its overall goal, trust in that team member deteriorates. So fear then begins to grow that the one who is not following through on their commitment to the group's goal is actually an enemy.
Enemies come in all forms.
The one who does not pay attention to detail because slipshod work means unreliability. The one who is obsessed with extraneous issues is another enemy. The likelihood of their achieving their goal is lessened. It will either take longer to do it or else it will not be achieved because the group gets distracted with being led off track or else defeated because their efforts are constantly focused on compensating for the one who has failed in their commitment. And what you say is exactly true when it comes to groups and interactions.