You're being quite sloppy with categories. You've shifted from saying "if an action is good, it is good regardless of your lot in life" to talking about people being more or less good, based on wealth. Nothing else in the conversation so far assumed a moral status in people; only in actions.
Categorizing people by power follows from the fact that power enables actions unavailable to the powerless. I cannot meaningfully shift public opinion on climate change. Someone investing a billion dollars into cultural messaging probably could. The same ethics could apply to me and the billionaire: say, a rule of maximizing one's impact on the phenomenon most likely to negatively affect the most people. Now if you assume (as you seem to) that utility isn't part of the morality equation, then both I and the billionaire could each try our best and be equally good. But that's not an obviously true thing, and I think most people these days would assume that ends matter. In that light the billionaire can do more good than I can, and although the same ethical rule might apply to each of us, it's proportionally more relevant to the billionaire. So: an ethics for society's leaders.
Categorizing people by power follows from the fact that power enables actions unavailable to the powerless. I cannot meaningfully shift public opinion on climate change. Someone investing a billion dollars into cultural messaging probably could. The same ethics could apply to me and the billionaire: say, a rule of maximizing one's impact on the phenomenon most likely to negatively affect the most people. Now if you assume (as you seem to) that utility isn't part of the morality equation, then both I and the billionaire could each try our best and be equally good. But that's not an obviously true thing, and I think most people these days would assume that ends matter. In that light the billionaire can do more good than I can, and although the same ethical rule might apply to each of us, it's proportionally more relevant to the billionaire. So: an ethics for society's leaders.