The kitten is called a poor kitten because even after trying her best and working so hard to get to the moon which she thought was a bowl of milk, she could not get it and just did not realise that it was actually a moon as she had never seen it before. Her innocence and cluelessness make us feel bad for the kitten and that is why she is called a poor kitten.After she starts returning to the porch she sees that there is a bowl of milk there which is the real bowl and real milk so she is considered lucky and blessed to have got what she was after all night, it was quite like she deserved it.