Why shouldn’t the poor also contribute to a better society? Within their means, of course, but they should not be exonerated from the contribution game.
Obama wants to raise taxes for the rich so that they can share in the sacrifice. Sharing the sacrifice is reasonable if it is productive. However, once the rich sacrifice their funds to the government, the politicians misuse them and spend them indiscriminately. Why contribute to governmental theft? Why sacrifice to carelessly corrupt government institutions?