I don't know if you caught it on @lukestokes' blog, but there was a link to an excellent piece by "The Oatmeal" that touched on much of what you're talking about here. It's worth a gander...

When I read your list, what came to mind was "boxes." Boxes are nifty things people can put their ideas of reality into... and use as a substitute for self-inquiry, critical thought and analysis. It's a way to not be personally accountable... and instead engage in pre-packaged group think.

I cut people more slack these days than I used to because "staying awake" at all times is a lot of work, and most people are just too tired and worn out to be mindful of their own biases at all times.

And you're exactly right... we need to be open and not just dismiss things out of hand "because it's from MoveOn" or "because it's from Breitbart." I've gotten useful snippets from both... it's interesting, though, a lot of people call me a "wishy-washy intellectual" because I look at many sides of an issue rather than attach myself and get entrenched in a specific paradigm.