I think his point is that liberals are reticent to complain now because they don't want to cost him the election, not that Obama should wait to go left. Personally, I'd rather Obama over Romney for a likely Supreme Court appointment alone. But not for much else.
Your response to cgod is what the article is defining as "not holding Obama responsible." You have brushed past all of the things listed only to find another reason not to vote for Romney. And hey, I get it. I'm not voting for Romney. I bounce live in between a solid blue state and a solid swing state ... with my state residency in the blue state. I have been tempted to change residency to my swing state digs just to feel like my vote for the "Screw-torture-we'll-just-murder-your-ass-with-a-robotic-death-squad" President will mean something! But I haven't nor will I. I love this place. ¡Viva Cascadia!
I honestly don't think it's brushing past those things to choose the lesser-of-two-evils. I am fully aware of my discontent. Each candidate has plenty of reasons not to get my vote, Romney just has more. It probably felt cathartic for Conor Friedersdorf to write this article, but I bet he will vote for Obama.