Because nothing says Merry Christmas Happy Holidays like a Christmas Holiday ornament on the White House Christmas Holiday tree with a picture of Mao Tse Tung on it:
...and the one with Obama's face engrained into Mt. Rushmore is also a nice touch that reminds all of us that the holidays are not about selfish indulgence but rather a time for giving and sharing.
As for the Mao ornament, so what if he caused the deaths of up to 70 million people, seasons' greetings from the White House everybody!