I haven't read any of Dan Baum's books, but I've enjoyed his magazine journalism for years and the man has a natural talent for writing online. His account of being fired from the New Yorker done as a series of Twitter tweets is a ground-breaking experiement in the form.
I also like what he has to say about the importance of editing for writers. As an editor by trade myself, I like to believe I contribute a thimbulful of worth to the universe, but beyond that, I've seen countless editorial examples of bad pieces rescued, good pieces made better, and great pieces left alone, all of which convince me that writers desperately need someone to keep them honest. Nearly 100 percent of the unedited writing on the Internets — including this blog — cements my case.
In my own professional experience the worst writers are the ones least amenable to editing, although occasionally some very good freelancers will also fight you for every comma; it's difficult to generalize. But if I may play Dr. Phil for a moment (read the next section to yourself in a Texas drawl), I would say that if you're a young editor and dealing with a new writer for the first time and that person has started issuing ultimatums before you've made a single proofreading mark, you probably don't want to throw yourself into a long-term professional relationship.
So I recommend and endorse what Baum has to say here about the important role editors have played in his professional life.
I'm dealing with this now on my second novel, which needs another run through the lathe. I must focus on submitting to the wisdom of my fine editor while the psycho writer part of myself wants to retreat behind his usual mud-and-wattle defenses.
P.S. That said, bad editors are horrible and should be avoided like H1N1. Unfortunately, you probably won't be able to recognize them until they have already begun their work disfiguring your professional reputation.