I'm sorry if I think "democratic" supporters are naive...but I do.
I support the Democrats because they are slightly to the left of the traditional Republican line. Are they "left enough" for me? No. Then why don't I support a 3rd party, like the Greens? Because the Greens will never gain power. Ever. 1.) They are disorganized, 2.) more importantly, our election system will never allow the rise of a 3rd party. See:
Duverger's Law. If a 3rd party does miraculously come to prominence, it is always at the expense of its closest aligned "major" party, splitting the vote and handing power to their common enemy. See: UK's recent election, where the "left" won the majority of votes, yet the right won power. If a 3rd party becomes powerful enough, it will simply replace one of the existing 2 major parties and just become "the other" major party of the 2-party system, leaving the overall system, which is really the problem, mostly intact.
Then, you say, if the Greens replace the Democratic Party, wouldn't that be better for leftists like yourself? No. The Greens will be forced to expand their tent to include centrist and center-right candidates, just like the Democrats did. To be a "major" party is to be a big tent party. The Greens will simply be the Democrats, but with a different name. Without
election reform, supporting a 3rd party is an ultimately futile endeavor. Is this a "naive" standpoint? To me, all the people jumping up and down about supporting 3rd parties are the naive ones, and I have illustrated why.
Ironically, modern Progressives can learn a lot from the Tea Party and how they've managed to push the Republican Party further right than ever before in American history. They saw the 2008 election defeat not as a reason to hand-wring and re-evaluate their beliefs and policy goals--they saw it as a test of
faith. You see, they are True Believers™ in their ideology, and like fundamentalists everywhere, defeat is viewed as a test that must be overcome. Re-evaluate their beliefs? No, they doubled down, organized, agitated, and primaried the Hell out of more "centrist" Republican candidates. Now, 2010 saw quite a few Tea Party darlings go down in flames, but the goal is not necessarily to win elections; the goal is to push the party toward your views. That's what Progressives used to do. From the 1910s to 1970, Progressives knew how to make the political system work for them. Somewhere along the way they forgot how. The irony is the Tea Party might re-teach us that lesson.
The only angry person in the conversation is you, that is obvious. Maybe I'll have to start visiting the other forums around here a bit more 
Of course I do agree with not destroying the planet, but I don't think a political party should have a one issue platform. I also find green supporters and candidates quite flaky and (everyone's favorite word) naive. I think that the best option now, with "democracy" really showing its true face (two party same ideology, basically a corporatocracy) is to not vote at all. Seems like people are already realizing that, in canaduh we get just over 50 percent generally. Not sure about the US, I think on Bill Maher last night he said 11 % of 18-25 year olds voted (not sure of the exact numbers)...low anyway. The less people that vote the less the system is legitimized.