Many many people travel to kenya every week for business and tourism. People please do not rely on your governments for whether or not you should travel, the net is here and will tell you everything you need to know honestly.
Not sure about the US State Dept but the UK gov is now in the habit of warning people not to go just about everywhere, its called covering their arses and being able to say we told you so if by some small chance something does happen.
Its a consequence of this crappy sue everybody culture we now live within in the Western world.
You will have the time of your life, knowing a local is the best way to go and Kenya has loads to offer.