Ender7 has claimed that a child's education shouldn't vary by his or her parents' wealth, but should be provided by society.

Wnewman's point is basically that when Ender7 says "society" he really means the specific nation that child belongs to. But by Ender7's logic this still isn't fair, because some nations are poorer than others. So unless Ender7 is willing to argue that it's immoral for some societies to provide better education for their children that others, than Ender7 is being inconsistant.