That's an awful lot easier but likely less accurate and what happens whenever establishment Dems lose. "Hillary lost because of Bernie Bros" is the first and loudest instance that springs to mind. But even if that statement were true, In hindsight we know that she and her campaign sorta rigged the primary, which looked more obvious than they probably intended. That disenfranchised some voters and they didn't vote.
That's not the voters fault, the candidate did something that made those voters not vote for them. Just like Kamala/the DNC did with running an ancient dude, not having a primary, running the ancient dudes VP, supporting the genocide of Palestinians, loving fracking, and onwards. I was really optimistic early on with her VP pick but that seemed to be the moderate leftmost edge of her campaign.
I'm of the opinion that until the DNC stops appealing to disenfranchised Republicans this steady slide right will keep happening. Running as R-lite hasn't really been paying off as well for them as it did in the 90s.
Why blame the people who didn't vote? They didn't vote for a reason surely, just as you and I voted for a reason. Just because their reason isn't the same as yours doesn't mean it isn't just as valid. Maybe it's ignorance or perhaps it's misinformation, but at this moment there's no way to know that, so discounting 10 million peoples conscious choice only serves to widen divides and alienate more people.
Blame Harris and the DNC for running bad campaigns and candidates. It's on them to win the voters and an election, and it should have been clear that 'the same campaign as last time and the time before' wasn't working.
No matter who we point at, we're going to have to start reengaging with our communities and supporting each other, and having those 10 million (likely somewhere left of moderate right) people on side going forward is vital.