He is missing the point. Jews don't take the OT literally, does that mean they are not really Jews?
Hitchens is trying to lump all "Christians" together into a mold he defines. The Bible has been taken by 30,000 plus Christian sects and interpreted differently by most. So, it might be convenient to lump all Christians into one group but it's not factually correct to do so.
Some Christians believe in a literal Adam and Eve, others DO NOT.
Some believe in a literal Noah/Flood, others DO NOT.
Some believe in a literal Jesus, others DO NOT.
No reason for Hitchens to be dogmatic on what is and what is NOT Christian!
That's like some Fundies saying JWs are not Christian because they don't believe in the Trinity. STUPID.