Ive been arguing with these folks for the last few days. It really is a case of letting perfect be the enemy of good. Yes, centrist democrats have their flaws. Yes, some hold views that are counter to current progressive movements. For instance, Newsom recently put out some anti-trans rhetoric. But it pales in comparison to what Trump and GOP are doing by several orders of magnitude. Whats really funny about these people is they expect the other side to compromise if their side wins the primary. Like the far leftists expect moderates to support their candidate if they win the primary, BUT THEY DONT BELIEVE THEY SHOULD DO THE SAME IF A MODERATE WINS. I also think these voices are coming from younger generations that think significant political change happens overnight, or over one election. They dont realize how long and how much effort it took to get things like black men the right the vote, then women, or even gay marriage which is still a work in progress as GOP is determined to go backwards (they also are trying to make it harder for married/divorced women to vote currently.)