They are mostly upset with how the Biden Administration avoids conflict through not being transparent. Not getting critical answers to what's happening on our southern border along with the retreat fiasco in Afghanistan, is leading more and more reporters to complain to their news agencies that they can't get the stories they were told to find.
This along with Jen Psaki who has never let the truth get in the way of a good story, and the White House reporters are livid that they're being lied to. Not even sneaky lies, just outright blatant lies that they generally hope the media will provide them with cover for. Fortunately for us, they've angered the media enough to where some of them are asking the hard questions and not just Fox News.