At the moment, there are so many arrogant, careless, agenda-driven "journalistic professionals" wandering around in MSM-land that it's a target rich environment for observant fact-checking bloggers.
Since MSM editors and producers have been falling down on the job, they have no one to blame but themselves when bloggers whittle their shoddy subordinates or shoddy selves down to size and, in some cases, drive them off the field.
So, "media professionals", that idea of accountability that you've made so much hay from applying to politicians, physicians, business executives, and others not in the chattering class? Now it applies to YOU too. Get used to it, or find another line of work.
It's a kind of "internet street justice" applied to journalistic malpractice. They just don't like the idea that they have little to no control over independent-minded people having access to power.