Reeling him back in simply means that everytime Hincappie made a break for it T-Mobile chased him down. There's no sense blasting down the road when you're dragging your competition with you.

If he'd been in a break that made it to the finish, Hincapie could have gained enough seconds to earn the yellow jersey. Even if the break didn't make it to the finish, he could have gained enough bonus seconds at the intermediate sprints to take the jersey.