This seems like a willfully ignorant reading of the op-ed. There is context here which any reasonably well-informed person should be aware of, which is that the gains made by top earners far outstrip the gains made by middle and lower income people. As a result, those people are worse off than they were in the past (their income has failed to increase relative to cost of living increases in recent decades.) So the reason people focus on the wealthy is that middle and lower income people are already at their breaking point.
Also, it isn't clear to me if you're referring to the "Buffet Rule", or to a scheme like the one proposed by Buffet here. In any case, he admits that even if we did the first part of what he is proposing (the minimum tax for the wealthy), there would still be work to be done.
"You hear a lot, in books, in the blogosphere, among pundits that the middle class is being hollowed out, the incomes for all but the top 1% or maybe the top 20% are stagnating; that the gap between rich and poor has grown inexorably; that the American dream is dead"
"[these claims] are basically wrong. And that's what 10 years of research by myself and James Sullivan at Notre Dame has shown. If you measure incomes better, accounting properly for inflation, median incomes have gone up by about 50% since 1980. And if you look at consumption, it's gone up by a similar amount over that whole period--though exactly when it went up is slightly different from the income pattern."
Also, it isn't clear to me if you're referring to the "Buffet Rule", or to a scheme like the one proposed by Buffet here. In any case, he admits that even if we did the first part of what he is proposing (the minimum tax for the wealthy), there would still be work to be done.