I think both sides of the argument made by Moore and Hitchens are correct and incorrect.  Moore basically wants to blame the whole thing on Bush which is wrong.  I do believe however, that there may be some kind of relation between the two (Saudi Arabia and the Bush Family).  In his documentary he tries to blame George W. Bush for taking inappropriate actions towards Saudi Arabia.  He argues that Bush should have sent more troops into Afghanistan which would have limited the number of Taliban members escaping.  In Hitchens critique of the film he clearly states that Moore has based his entire documentary off lies.  This does seem very true because when watching the film many times I noticed Moore trying to influence my opinion.  Overall, I would lean more towards agreeing with Hitchens.