I read somewhere an article speculating why Obama was not a fan of Churchill. Seems Churchill is not the beloved statesman and WW2 hero in Kenya because of his role in putting down the Maumau rebellion there.
Here's an unrelated but telling story about Onyango from Dreams From My Father, and another reminder to listen to the whole book if you haven't done so yet.
http://www.twodoctors.org/2009/02/obama-churchill-the-mau-mau.html
Obama shows his true allegiance.
Another reason - Churchill had nasty things to say about Islam.