My Haruhi knowledge is fail but I think it's a parallel to Mikuru not being able to interfere with the timeline, therefore not letting herself come between Kyon and Haruhi.
… I'm sorry.IAhAH!Just for now, I think it's okay.IDo you know the story of princess Kaguya?Since she had to return to the moon some day, she didn't want to get too close to anyone.Ah!AH!..AH~~!!<3<3Haah...HIAAA...