Why bail out Air India, but not private airlines?

Government runs Air India, it messes up big time, so much so that it did not have money to pay salaries of employees. Now it intends to spend about Rs. 20,000 Crore of tax payers' money to clean up the mess it created.
Well, one argument can be that it was not entirely Air India's fault. The Airline industry across the world has been hit by slowdown, and it may not be in national interest to let Air India die. But then why it is not inclined to bail out private airlines? In first place, a common man will ask, as to why his hard earned tax money should go in bailing out something like an airline? How many tax payers use them anyways? But assuming there is a valid reason for that, why bail out an airline owned by Government and not the ones owned by private entrepreneurs?
Can government be whimsical and behave like a grumpy grand ma to say that it will do what it likes, without giving any reason?

Here is the news article:- http://www.hindustantimes.com/StoryPage/StoryPage.aspx?sectionName=HomePage&id=53c78634-992d-4f45-a7fe-83502f0947e9&Headline=No+bailout+for+pvt+airlines+Govt+warns+punitive+action