I am (or was) tempted to say that the Dems just don't want to get into the weeds over something that wouldn't change a single vote, but I'm less certain now.
Case in point: Elizabeth Warren was apparently told by her mother that she had indigenous American ancestry. (And she does, but it's not much.) Who knows why her mother said that. Maybe she wanted her daughter to take pride, and she actually was told the same by HER mother. But the point is, she never profited from expressing that claim, and no one was harmed by it.
On the other hand, Frump the Plump Grump (and his father) deliberately lied to potential Jewish renters in NYC in the 1970s and 80s. Coming some 30 years after the holocaust, many Jews would not have rented from people of German ancestry, so for money the pair of them outright lied, famously claiming to be Swedish.
There was nothing I listened for for greater anticipation than for Warren to rip into Fiddle Faddle with that truth in a vulnerable moment. (And I still do.) But while I have no problem being Dem Blue, being blue from holding my breath seems a bit old.
Perhaps you're aware, but for months prior to Nov. 2016, Mother Jones (one of the best news sites I've ever read) ran a daily article they called "The Trump Files", and they are now running them again. If you haven't seen this feature (available to binge), you're in for an experience both entertaining and sobering.
Stay safe.