I don't think anyone's been that unpleasant about her - it's more a general sense of incomprehension that she's suddenly turned up on the cover of Vogue Italia.
My abiding memory of her is the sycophantic article that UK Vogue ran about her - stating she had a noli me tangere stare - so it's evident that she's well-regarded by some magazines.
And I hesitate to criticise her that much, because I do believe there's a place for all sorts of body shapes in fashion. And I don't really expect her to have achieved that much at the age of 18. Plus, smoking and drinking is typical behaviour for teens, whether your father is famous or not.
But similarly, I don't find anything that special about her, she's a bit blank to me. Her sister might drive people insane, but she's got something that makes people interested in her. That cover shot isn't bad, but it doesn't make me want to know Pixie better.