I agree it is not explicitly Christian, but it is explicitly religious. Only a god can be the designer. If the designer arose by abiogenesis and evolution, no matter where that happened, then the designer could not be intelligent, by definition.
Though I am a Christian and do believe that the God of the Bible created the universe, ID makes no such assumption that a god created the world. As I understand the theory it could literally be anything - aliens from outer space or a time traveling band of intergalactic space hippies. I am being facetious, but you get the point.