I can't remember specifics, but a few times over the years I've heard this "excuse" expressed by journalists about why their "objective" coverage was perhaps maybe not quite as objective. Basically, it's because they know things the mere mortals known as the public don't know, and that those things justify monstering a candidate over anything they can make stick because.
But of course it's bullshit. Those secret things they know would be reported if they were important and, you know, verifiable. I'm sure gossip is currency in our political press corps, and most of these "things" are stories traded at the bar. "Everybody" knows them, they just don't know if they are true, though they probably think they know it.
Leaving aside the fact that what's plainly obvious about Donald Trump is clearly worse than any secret gossip about Hillary's role in killing Vince Foster.
One could pick apart the whole thing - oh, yes, the Clintons are the only presidents to hang out with "Wealthy McWealthersons" - but basically it's the kind of thing which confirms every liberal fear about a vapid, preening, self-important, privileged, and ultimately very stupid political press (#notallmembersofthepoliticalpress).