Can't say it's not leftist. It may be based more on supporting a Democratic party agenda, but it's still a leftist site.
The great majority of members are liberals, of course. But those that are too extreme (like the "9/11 tin-foil hatters") meet a grisly end. Just today someone wrote a diary attacking Harold Ford and urging Kossacks to vote Green. He was troll-rated and met with comments like "this is a Democratic blog, not a liberal blog". That's why it's frustrating when blatantly uninformed people say DK is a socialist website, or whatever.
Do you actually post there, btw?