Bernie’s social democracy has a libertarian feel, not only because Sanders himself is a stout civil libertarian, but because for lots of reasons (good and bad) the US doesn’t have the same overarching officialdom (Josie Appleton’s “busybody state”) that has taken over many of the European welfare states, even as they implement austerity. (My brother and his wife have horror stories of the layers of bureaucracy sewn into everyday life when they lived in England.) Bernie’s plans play to the good parts of that as they are universal, easy to understand (Medicare for all paid for by a progressive payroll tax), and not only don’t infringe on personal freedoms they substantially increase them.
It’s often the Vox inspired liberal, the one who fetishizes means testing and builds policies based on nudge theory, who wants to enshrine officialdom into our lives. (The Obamacare disaster is a key example.) This is mayor Pete’s, and even Elizabeth Warren’s, constituency. They represent the public/private partnership for perpetual paperwork. (How’s that for alliteration?)
This is one reason why Bernie does well outside the cities. People understand the difference between something like social security and another convoluted targeted policy plan. Populist universalism sells, technocratic wonkishness does not.