Urban slang definition: The Twitter version of welp signifies the speakers reluctance or lack of enthusiasm for something that is finished or unchangeable; it is, roughly speaking, a linguistic shrug, which you might imagine as a combination of well and a gulp.
To your earlier question, when Dunne's writing becomes petty, personally insulting, and seemingly vindictive instead of merely being critical then you'll know he's "gone hack," until then you're just being obtuse.