Bill Clinton saying "We're all Eisenhower Republicans here"
Obama claiming he would have been a republican before the conservative revolution
Hillary trying out her fucking GOLDWATER credentials to get elected.
And there's Biden talking fondly of Strom Thurmond (Although at least he didn't try to claim his political legacy)
Who are they trying to appeal to? Anyone who likes Goldwater isn't going to vote for a Democrat, ever, and anyone else who knows who he was would hate it.
They just don't have the idealistic blinders on. About 30-40% of dems poll as conservative on many issues and there are Goldwater voters in the Dems due to the way party affiliation has shifted. Stuff like the police funding, parking the trans bills where they can quietly die, the border stuff, abortion, etc, isn't an accident. The Problem Solvers Caucus within the dems is an entire group of Manchins and Sinemas and it is at least 3 times the size of the squad while functioning as an actual voting block.
I think people also remember the Obama quote, but don't remember that when he was openly saying that stuff the DSA was campaigning for him the same way it would for Bernie later. So there was no real consequences from the left at that point. Progressives were so deep into self delusion Obama could afford to be honest about what his ideology was and what he intended to do pretty often.
Electoral politics starts to make a lot more sense when you get pilled on the fact that half of US voters - including 30-40% of Democrats, as you said - are conservatives. The reason why US politics is so fucked is because TV news has manufactured a ton of conservative consent. Voters know what they're voting for when they elect these right-wing ghouls.
"Joe Biden sucks" and "Joe Biden is to the left of 80% of Americans" are both true statements, and they're not mutually exclusive. Manchin is probably to the left of two-thirds of Americans, too.