So instead of looking to compromise, let's move the party in the farthest leftward position we possibly can. I mean, look at how President McGovern did!
That was a fundamentally different time. Not all time periods have electorates primed with the same opinions about how things should be run. I can see why conservatives would mock the idea of moving left, but that is to be expected. To say anything else would essentially be admitting that America wants more liberal policy.
Millennials and most likely gen z will be perfectly fine with, and arguably
want a leftwards shift away from the more moderate/conservative politics of boomers/silent generation voters.