well, I could see two reasons why Morrison may not openly criticized that scene. Either he doesn't necessarily consider it a "superman" story as much as a "DC Comics" story, or it's just that he doesn't openly criticize Mark Wolfman nearly as much as he does Moore.

On top of that, Morrison probably dislikes this story BECAUSE Superman loses his friends, his dog and is forced to take a life.
That "superman doesn't cry" is just a way of saying that such elements shouldn't be part of the "last" superman story, because, to Morrison, the ideal "final" superman story should be on the highly idealistic side of things, one which still ends with Superman saving everyone.