Part of it too is there's no traditional punching bag they can blame.
She didn't have a primary, can't blame a "contentious primary" that "gives ammo to the GOP candidate" - there weren't enough votes for 3rd parties to say if only the greens voted for the Dems they could've won - they got to run the exact campaign they wanted, nobody in the party was fighting for control like a Bernie wing, the oppressed minorities mostly acquaiesced quietly - and to top it all off, Trump won the popular vote and kept a lot of his 2020 vote.
So the wild rage has no target and the media doesn't actually care all that much that the Trump transitioning is happening despite the hand wringing, so there's no one to triangulate the insider dem commentariate's rage. And they cannot accept that they themselves are to blame, almost like congenitally
They've never had to face the music like this before and like a child that was never held responsible - in this case quite analogous to a rich kid who got away with being a hellion in school and then hit the real world - they're freaking the fuck out.
I've seen some of them blame it on her campaign being too short, but they can't even take that angle to it's full extent because it might make Genocide Joe look bad for not stepping down sooner.
It is 100% true when you realize the "base" they are referring to is the democrat faction of the oligarchy. They certainly were energized enough to throw away $1.5 billion on her.
White libs were energized for Kamala because she benefitted them.
White libs also think the world revolves around them and any opinion they come up with is the majority opinion.
They can never imagine a minority of any group not gleefully voting for their candidate because in their eyes they truly think they're the most progressive a person can be