It's hard to say. More than likely Gaara and his siblings aer helping Konoha because they discovered they were betrayed by Orochimaru. Perhaps Gaara is the Kazekage (who would deny him?) [img]i/expressions/face-icon-small-wink.gif[/img]

But...I feel that Gaara is questioning is purpose in life. Remember, Gai protected Lee from being killed in the Preliminary matches and Gaara didn't know how to take it. He thought about it constantly and became unhinged (remind him of his uncle).
Then with Sakura protects, Sasuke (I think) protects, and then Naruto protects and gives his all. Not only that, but Naruto spares Gaara. Though Gaara may be under orders, there is providence, as it were, for Gaara to aid Lee and not the others.