From your link,  "In a statement released Monday, Clinton’s transition office said every item they accepted was identified by the White House gift office as a present to them. They said none of the gifts taken was on a curator’s list of official White House property.  “Gifts did not leave the White House without the approval of the White House usher’s and curator’s offices,” the statement said. “Of course, if the White House now determines that a cataloging error occurred, ... any item in question will be returned.”

So they had approval to remove the items, the approval was given in error, and items were returned. 

Your characterization of this as stealing is a little off.