The problem is center-left political elites see the movements engineered by their right-wing colleagues as legitimate because they're all part of the same club, they themselves are rather nasty people, and they assume "the unwashed masses" are even worse than they are.
They're also fixated on goals that have nothing to do with improving the average person's life so even when they want to oppose the right, they fail because they can't conceive of or articulate a position that would help.