Politics, and the media. The operation was late, Task Force Ranger were four weeks behind schedule and politcians were getting nervous. The media had not yet gripped on to the story, leaving war weariness out of it.
Once the Battle of Mogadishu occured, despite the massive success of the mission, the pictures of Super Six One and it's crew hit the war home in the U.S. And the media clung on to the deaths of those U.S soldiers , which naturally caused the U.S public to stir in it's seats.
These reactions from the U.S public, pressure from up high because the operations were running late, and from the U.N because they wanted increase in peace talks ... led to Task Force Ranger being removed from Somalia .
Politics , as always.