This is so true. I was mostly talking about the online leftist cohort, but there's another (larger) group of older libs who simply haven't had a software update since the 2000s.
A boomer acquaintance fits this category, he was recently boasting about how Trump's base was "deserting him" because he'd seen the National Review criticizing something or other. Absolutely no concept that National Review is a neocon establishment rag that was never for Trump. In his head, the "right wing" is still a monolithic bloc of conservative Christians in suits trying to put prayer back in schools.
And the weirdest thing is that these aren't people who ignore politics (which is something I can admire). They think of themselves as politically informed and many of them talk about Trump more than anyone here does, but they somehow still manage to live in a 2008 bubble. It's uncanny.