All theists are not alike. Christians should not be blamed for the excesses of Muslim fundamentalists.
Similarly, all atheists are not of one mind. I doubt that Hitchens is a fan of Stalinist or Maoist communism.
Maybe not now, but he did start out as a Trotskyist.
Quite recently (2005-6), Hitchens described himself as a Marxist and expressed admiration for Lenin and Trotsky, at least according to Wikipedia.
Even if you leave Stalin out of the picture, Lenin and Trotsky have a lot to answer for.