"Hack" is an insult for a bad journalist, especially a partisan one. Here, it's applied to people who behave like hacks.
"Hackery" is the act of being a hack.
I've looked at every definition of "hack" and none are that one. Usually a hack refers to one who has a quick job to do and isn't really good at it. I've seen no specific reference to journalists other than stuff like this:
1. a person, as an artist or writer, who exploits, for money, his or her creative ability or training in the production of dull, unimaginative, and trite work; one who produces banal and mediocre work in the hope of gaining commercial success in the arts: As a painter, he was little more than a hack.
I just find it interesting that one would never hear the term "hackery" anywhere but on THIS MESSAGE BOARD.
yeah, I know this belongs elsewhere, but no one would read it if I'd put it there.
sorry.