They flock to the Republicans because they're socially conservative and often racist. They don't support BLM, certainly don't support the idea of socialized medicine and they're absolutely anti-choice. That doesn't even get into the 2nd Amendment or immigration. These voters hate liberalism and feel the Democrats are too extreme on social issues.

There's no changing their minds without adopting the conservative ideology.

It's that simple and if Bernie doesn't see it, he's woefully naive and maybe needs to retire.