This is the thing with people who are too impatient for incremental progress. Progressives are, by definition, more progressive than the average. So when everyone else is not keeping pace with their ever-evolving standards they think those people are running backwards. And then they call for burning down the whole system because they want their cake now or else no one can have any ever.
They truly can't see how far things have actually come. Anyone who says the Democrats keep moving further right has no idea what the 20th century was like.