They were unable to do so when Obama was President or Hillary was running for office.  Now that the wheel has turned and the pendulum has swung, they will be able to be zealous in their "watchdog" role!

Of course, Trump does not seem to be interested in being 'watched' no matter who the 'dogs' are!

He specifically appears to have no intention that he or his 'message' be interpreted, modified, screened, ignored, or otherwise affected by the 'media' unless it is in his favor.  

He can Tweet what he wants, when he wants and about what he wants and the media can take it or leave it.  His base will probably take it; his 140 characters are easier to absorb than listening to a half hour 'analysis' by five people shouting over each other.  

He can have as many press conferences as he wants, or not.  He can choose to answer a question from any 'reporter,' or not.  He can choose to take them on Air Force One, or not.

He is the President; they are not.