Bitterness is baked into this very Web site. There's a passage in the META information up front that says, fairly unequivocally, "A bitter, dying man takes one last shot at the society that perturbed him; well, maybe he's not dying, but he's definitely bitter."
Of course, we're all dying, albeit at different rates; "health," I am inclined to believe, is nothing more than a slower-than-normal downward spiral. (If "downward spiral" seems unduly harsh, well, Nine Inch Nails is playing in the background as I write.) And maybe some of that bitterness is due to knowing that The End is inevitable and not knowing what to expect afterwards.
However, absolutely none of it is due to anything Barack Obama imagines:
You go into some of these small towns in Pennsylvania, and like a lot of small towns in the Midwest, the jobs have been gone now for 25 years and nothing's replaced them. And they fell through the Clinton administration, and the Bush administration, and each successive administration has said that somehow these communities are gonna regenerate and they have not. And it's not surprising then they get bitter, they cling to guns or religion or antipathy to people who aren't like them or anti-immigrant sentiment or anti-trade sentiment as a way to explain their frustrations.
Points that need to be made:
Communities do not "regenerate."
People become bitter for many reasons, not always political.