I agree that a generation being "born between years A and B" is a false distinction, but on the other hand I think there's something to be said for a "cultural generation".

For example, Baby Boomers are children (supposedly) born between 1946 and 1965 or so. Yet, "Baby Boom" cultural experiences are entirely different for those born in the late 40s and those in the early 60s. A late 40s "Boomer" would have been taught "duck and cover" in elementary school, drafted for Vietnam, attended Woodstock, etc; an early 60s "Boomer" had completely different experiences growing up.

After typing all that out, I realize there's not real point except to reiterate that I agree with you about the definition of "generation" and provide some illustration of the point. Otherwise, I agree with Tom that while OWS may have some legitimate greivances they botched presentation beyond belief for having them taken seriously.