I think that's a pretty thin synopsis of the Bernie left, nearly a straw man. Pretty sure none would argue it would convince the MAGA, and they don't matter. I won't argue it. We all did that a long time ago, and it did us no good.
Bernie moved on to work with Biden and helped create the Bills that have moved the country forward - now known as Bidenomics. Cool.
You're maybe thinking of the total leftists that want nothing to do with Dems and duopoly? Anyway lets move on.