A close shave with the criticism question

Pamela Philipose, the public editor of The Wire, raised an important question towards the end of her latest column:

Sudhir Angadi wants to know why The Wire is “loaded with so much of negativity”. He wants a response to his question before he decides whether he will continue to read its content. Around the same time I received another mail, this time from S.P. Mahapatra, who also found the lack of “positive news” in The Wire distressing. …
Fortunately, he took the trouble to send in his suggestions: “It will be better you write good pieces on the policies of the BJP government and their work over  the last four and a half years; how leakage of public money has stopped through the introduction of Aadhaar; how millions of poor people now have gas and electricity connections; how hundreds of thousands of children are getting immunised; how LED bulbs are being distributed at a cheaper rate and neem-coated urea has been introduced to stop the black marketing in urea.”

But after having come so close, she lets the answer drown in the (legitimate) righteousness of The Wire's political journalism. As an employee of The Wire – but more importantly as an editor as well as a reader, I'd like to know the extent to which a focus on criticism is justified in the journalistic enterprise. Indeed, all criticism is fair if it is accurate. However, does that warrant a focus on criticism alone in one's coverage of the news? That is the question I'd like answered. I don't prefer that the answer be 'yes' or 'no' either; I am only interested in the reasoning behind it.

Additionally, I suspect that when a person doesn't see what my issue is, it's likelier than not that they implicitly believe journalism is synonymous with adversarial journalism. Criticism can emerge in other, non-adversarial contexts as well. In science journalism, not all stories have to end with piercing state-sponsored veils of secrecy, to use Philipose's words, and meaningful journalism is to be found as much in the courteous cross-examination of research methods as in questions raised to research administrators.

In this context, outside of the requirements of political news, could an exclusive focus on criticism be justified? Or is one required to "balance" it, in principle, with positive commentaries as well?