Waaaait, what? Progressives not seeing things in black and white?
It's always been the centrists who don't see things in black and white. If you don't see things in black and white you realize, "Wow, okay, that conservative point is actually a good point (just that one, not every one)" and/or "Huh, that's what the 'libs' all think and...this one...totally makes sense."
The only time when "progressives" don't see the world in black and white is when the label is allowed to encompass some of the center (just like with conservatives).