Because hew was a citizen and thus entitled to one.
Why would he want one when a U.S. passport would have been easier to get? Might be advantageous in some parts of the world, to have an "Other than Western" passport. The additionally difficulty would not be all that much, if it existed at all.
Even though he never lived there and had no connection with the country since the age of 3?
Might be advantageous in some parts of the world, to have an "Other than Western" passport. The additionally difficulty would not be all that much, if it existed at all.
And the fact that there is absolutely no evidence of any kind that Obama had a Kenyan passport doesn't deter you in the least, does it?