You’re joking, right? They’re the majority of the active voters on the left. It’s progressives that protest by abstention and vote third-party when they don’t get an ideal candidate. Turnout cost Democrats the election in 2016, then we got Biden, not Sanders in 2020.
Those polls are exactly why the DNC keeps moving candidates toward center. They try to capture the reliably active voters rather than roll the dice on the inconsistent participation of the far left.
I voted for Bernie in the primary, and Hillary in the election. I know many who did the former, but did not do the latter.