This really all began with Obama - remember the pix of the little kids in uniform doing military drills and saluting Obama? He used being (marginally) black to excuse and cover up the true nature of his project and to claim leadership of a sector of the population (which he used as a threatening and empowered mob).
They couldn’t legally get a third term for Obama. While anointed heir Hilary was satisfactorily vicious and corrupt and had the woman shtick to “justify” it and bring in her sector of the population as a mob (notice how many of the legal attacks on the Supreme Court justices, conservative politicians and others have been led by shrieking, hysterical women), the Dems couldn’t quite pull it off because they hadn’t fully developed their vote fraud techniques and Hillary had a lengthy and bad track record and was just plain not liked.
Also, everybody but me seems to have forgotten how the Dems actually challenged Trump’s election in 2016, how they slowed down all of the normal change of office procedures with their challenges, and how they continued to reject him as legitimate and put roadblocks in his way when he took office.
They’ve been working on last night’s speech for years, really.
It certainly is a current DNC strategy. Crist took out after DeSantis with a similar comment about Trump voters.