Bullshit, plain and simple. The Dems helped gut worker protections, gut welfare, gut student financial aid, and gut bank regulation. Dodd-Frank put a band-aid on the wound left by the repeal of Glass-Steagall but certainly didn't advance any type of liberal economic agenda. The Reps are the party of the filthy rich, the Dems the party of the merely rich.
So basically you're just going to make up nebulous ideas and declare yourself right in the face of empirical evidence. For example, Dodd-Frank is a VASTLY larger and more comprehensive regulation of Wall Street than Glass-Steagal ever was.
Let's talk specific positions of the median Democratic Party number in 1980 vs. today. Tell me what they wanted then vs. now and how they have moved to the right.