The Spectator article is not about justifying disreputable, twisted, tendentious, malignant articles in the DM. That should be clear from the title, not to mention the contents of the article. It is about defending freedom of the press. Hacked Off appears not to understand how valuable a thing this is to a democratic society, regardless of whether on agrees with which ever 'side' or publication is publishing disreputable, twisted, tendentious and malignant articles which, in themselves, cannot be justified.
The argument for freedom of the press (and freedom of speech/expression generally) would apply if it had been one of the politically left-wing papers that had broken the rules of decency.
Beats me why people don't understand this. Who was it who said "I disagree with what you say and how you say it but I will defend to the death your right to do so"? Or words to that effect.