It's a useful shorthand for the way in which the tabloids operate, I'd suggest, and the Mail does seem particularly good at striking a holier-than-thou line while perhaps not quite abiding by the highest standards of truth and honest (see one Mr H Grant for more details).
I can't help thinking that there's some truth behindthe various jokes which have at their core the notion of the Daily Mail's editorial team yearning for the opportunity to run a story with a headline along the lines of 'Euro Human Rights Law Allows Muslim Hate Preacher to Lower House Prices: What Would Diana Have Thought?'