Democratic Party members mostly hate their politicians. They're often seen as parasites. They just use the party to get elected. Dems would
love to have the kind of relationship Socialist Alternative has with Sawant. Though, in truth, the delegation for Ballard & North Seattle has been pretty good during my direct involvement.
Now that I've played the game a little bit, I don't understand the Corporate Democrat label. As Jesse James said, he robbed the banks because that's where the money is. Same for fund raising. That's been slowly changing on the left as parties wane and interest groups rise. That guy from QuarkXpress was an early pioneer of this model.
I now think of The Struggle as entities defending the status quo (establishment, duopoly) and everyone else storming the castle. That's neither bad or good; it just is.
And per Francis Fukamaya's vetocracy thesis, the connection between our party system and the widespread dysfunction in governance is fairly loose. Right now any one can do anything without much fear of repercussions, esp on the left. Said another way, I agree with Ezra Klein's thesis that if we make the (lowercase) democratic reforms to enable majoritarian rule, then the party system can grow to actually mean something.
I recognize that I'm way to the left of most participants. I have strong affinity for MLK, David Graeber, Jonathan Rawls, and maybe some others. I started as a Green and still (probably) believe in its platform. But Nader nuked that party. (I'm still mad.) And like most Democrats, I joined with the intent to oppose Republicans. aka Negative partisanship. I think this setup is terrible.
Back when I was attending all the third party meetups (Greens, Socialists, Libertarians), I was struck that those members were making an affirmative choice, standing for what they believed in. That's a much more healthy approach.
To feel that vibe, I've focused more on issue based orgs, vs party politics. Gay marriage, weed, sustainability, etc.
So I thank you for sharing some of your Socialist Alternative experiences. I need to go check them out.