The citing of generational divides has been a means for many to dismiss, defuse, excuse, or otherwise marginalize those ideologies with which they disagree. My parents often did this with their parents’ and grandparents’ overt racism; I sometimes catch myself doing this with my parents technophobia; I can almost imagine my future children dismissing my own philosophies as Gen-X angst. When Matt Bai writes, "These numbers [Pew Research Center opinion data on Pres. Obama] probably do reflect some profound racial differences among the generations, but they are more indicative of how young and old Americans approach the issues of the day, generally," he misses a much more profound point. Yes, cohort (a.k.a. generational) differences do matter and for two main reasons. First, older cohorts vote in much larger numbers which in a representative democracy means that their opinions are more likely to be translated directly into policy and legislation. Second--and I think this is the tacit point that Bai is trying to assert--older cohorts are closer to aging themselves out of the political system and, to put it crassly, are closer to aging themselves out of life. So, yes, ideas matter, but the material realities cannot be ignored. As much as we all might like to ignore their impact, race and class and gender and...all still make a difference. These effects have not gone away (yet).
Compounding all of this, younger cohorts are essentially doing the same struthious aversion as the older Tea Partiers in their denial of all realities contentious. Even if out of vogue, at least the greying NAACP points to social realities. The naivete of the Millennials and the self-interest of the Tea Partiers lead down the same pernicious primrose path.
People cannot change their "complicated journeys," but they can better inform their perceptions.