I worked as a volunteer and then paid staffer on Democratic campaigns for a decade. I know good and well the kinds of dirty tricks the party can and does use to ensure the "right" candidate wins a primary. The fact that you don't want to understand the argument doesn't invalidate the argument. The Democratic Party exists to give the left flank enough faith in the system to keep them from revolting, they serve no other purpose.

Blue MAGA is a perfectly apt term for the people who put party loyalty above critical thinking. The people who decry Trump's immigration policy but happily voted for Kamala when she ran on an identical policy. The people who don't believe that there were kids in cages at the border before and after Trump's first term bcs that would require accepting that Obama and Biden weren't much better than Trump. The kinds of people that believe Trump mysteriously appeared out of nowhere and refuse to accept the twin facts that decades of bipartisan neoliberalism made someone like Trump inevitable, and that Hillary Clinton's campaign allies deliberately pushed their tame media talking heads to normalize Trump, ensuring that the slide to fascism would start in 2016, when it could have been delayed another 10-15 years. The kinds of people who'll scold people with principles for not voting against those principles rather than blame their party for running a candidate that principled voters could not accept.

When someone loses a race, they shouldn't look at the comprehensive post mortem of the campaign and decide that since the things it says aren't acceptable to the donors they'll ignore it and keep punching left. But they did, and it doesn't seem to have dampened the enthusiasm of Blue MAGA in the slightest.