It doesn't help that most Democrat politicians are happy to maintain status quo. Or they're completely feckless, like Chuck Schumer, who is the absolute King of bringing a strongly-worded letter to a gun fight.
People that are actually leftist don't vote because there's nobody that represents them. Most Democrat politicians are centrist.
And this is my point, sometimes you won't have the candidate you need/want. But you don't bury your head in some kind of moral sand and allow a monster to be voted in office. You bite the bullet and vote for what's best at the time.