It is easy to get protective over something we do, that we feel is special, requires a certain amount of talent, skill, and a shit-load of hard work. So, it may feel natural to react negatively to a bunch of amateurs giving it a go and patting themselves on the back the whole way. Such is the world of National Novel Writing Month, and the accompanying attitude of those with a bit more concern about the quality of work than about total word count. Yes, I admit that I can't help but resent someone who's never even written a short story banging out over 1500 words a day. I wish I could do that. But my resentment ends there.
I have to think that NaNoWriMo weeds out a lot of would-be writers. It's one month of make-it-or-break-it writing. Like a jaded writing teacher, I want them to learn that it's damn hard work and if they're not cut out for it, better they learn now. But the whole idea is about encouragement, a healthy challenge among writers. That sounds to me like a good thing.
For more on the NaNoWriMo discussion: The Millions, Shaken & Stirred, Counterbalance, Mark Leahy at MetaxuCafe.