For some people FDR is the closest thing they can imagine to be progressive politics. The progressive-conservative switch in the Republican and Democratic Parties always makes for weird statements. You've got neo-nazis and neo-confederates controlling the Republican Party and Republicans say they are the party of Lincoln.
That's what Democrats have been trying to do since Bill Clinton. The Republicans have already been captured by the MAGA movement, where as the Democrats have yet to be captured by a movement. So for progressives and socialists, it should be easier to capture the Democrats.
GIven that I've had Tankies try to tell me the fight for LGBT rights isn't worth it because it's a "distraction" and "actually racist to force other cultures to conform to Western Values"
With how eagerly centrists have been throwing vulnerable minorities under the bus, it's clear that they bitterly regret the civil rights act and the voting rights act because they cost the party the support of the bigots they love dearly.
If you think they won't abandon you in order to chase nonexistent gettable Republican votes, look at who they already abandoned.
Republicans are obviously worse and I never said they weren't. That doesn't mean that Democrats are reliable allies, because unless your name is Netanyahu, they just aren't.