Well, that's not really what they say. Rather, the Guardian has mumbled something about how it slightly misconstrued something Tzippi Livni once said. No matter that what they did was to carefully edit a document so that it would say the opposite of the truth. Check it out yourself.
Using the Guardian's method it would be possible to prove that Yassir Arafat was a Zionist, that Menachem Begin was a supporter of dismantling settlements, or just about anything you'd like to prove. I'm reminded of a joke I once saw in Mad Magazine, probably 40 years ago, where they showed how anyone can cut words out of a brutal review to demonstrate that the author loves your product. Back then, however, it was intended to be so ludicrous you'd have to laugh.