Even if you believe that locality matters, EA principles like room-for-funding or focus on effectiveness instead of exerting effort for interventions still apply.

The best strategy to produce ethical behavior is simply to appeal to self-interest

That depends largely on your audience. For some people self-interest is very important. For other people fairness is more important. It's a mistake to generalize too much from one example in that regard.

Clare Graves's developmental theory for example groups people in different stages whereby different stages are differently motivated.