(Copied from something I just posted to Google+)
I think most of the people who find themselves anti-NaNoWriMo need to step back and figure out what they really have problems with, and try to focus on those things.
Be pro-editing, if it’s unedited and poorly edited books that bother you.
Encourage and educate people re: using Circles more effectively, to share posts only with those who are interested, if you don’t like your social media to be full of NaNo updates Oct-Dec.
Maybe just try to realize that there are power laws at play: Roughly/over 80% who attempt NaNoWriMo don’t finish (not even the word count, let alone an ending), and after doing it for ten years I can tell you that around 80% of those who do finish (as well as nearly everyone who doesn’t) have no interest in publishing their books – often they barely want it seen beyond their family/friends, if anyone. Anecdotally, I’d say that of the fraction of a fraction who have any intention of their book seeing the light of day, probably 80%+ know they need to spend time editing & polishing it (which is why NaNoEdMo exists, since much of the same need-a-goal-and-deadline still applies to any non-dayjob activity for a lot of people).
Oh, and then there’s the fact that, for me and most everyone I know who enjoys NaNoWriMo, it’s primarily about being social and having fun meeting other like-minded people while we all work on our own creative projects. Even the most curmudgeonly-anti-NaNoWriMo people I know tend to encourage activity of the same description, as long as it isn’t NaNoWriMo. Being social and collaborative and creative and building a network of thousands of local community groups all doing the same thing, all over the world, each allowing people to express themselves and make and meet creative goals and meet new people… Who cares if a tiny fraction of the creative work that comes out of it is professional quality? Do you rag on your grandmother’s knitting circle for not being aware of the market realities of the textile industry? Get a grip. Stop being anti- and find a way to be pro-.