As a writer, I have some additional problems with this crap. This is yet another example of trying to further codify the tropes that make so much mainstream literature so predictable. It's reaching the point where publishers and writers will only need to select their demographic of choice and fill in the blanks, MadLib style.
Now, don't get me wrong. The reason this construct is being foisted on the world of publishing is because of the success and relative merit of a coterie of authors who have developed a set of characteristics worthy of becoming tropes for the publishing world to exploit. It also means that those original voices will start to look formulaic as a sea of imitators rises around them at the behest of publishers looking for an easy marketing hook.
I also can't help but notice that the genre seems to be little more than an edgier more self-deprecating and confessional version of what has been called "Chick-Lit". Now that term always seemed more than a little pejorative and condescending so "New Adult" fiction may well be an improvement. Still, let's hope that there is a backlash against this kind of pigeonholing, because it is insulting to reader and writers alike.