I'm not responding to anything in a particular at the moment, but I have been thinking, as I often do, about much anonymity is abused by journalists (yes I mean journalists, not their sources). Low level whistleblowers need it. High level sources need it if they are revealing things they aren't supposed to reveal. It should be granted, carefully, to allow the reporting of newsworthy things that would not otherwise be reported.
There are many ways that it is abused, but one is granting anonymity to people simply to shit talk their opponents. This is not a good reason for it, and it privileges the people in "DC" who have press familiars, the ones with good relationships with the press, a problematic concept generally!
"Democratic strategist has been granted anonymity because otherwise everyone would know what a big asshole he is" is not a good reason to grant anonymity! Also, readers have no way of knowing if this person is influential or not, other than the influence granted by his pet journalist.