If everyone did that, lots of people would still die of preventable causes in poor countries. I think GiveWell does a good job of identifying areas of greatest need in public health around the world. I would stop trusting them if they turned out to be corrupt or started misdirecting funds to pet projects. I don’t think everyone has to donate this way as it’s very personal decision, nor does it automatically make someone a good person or justify immoral ways of earning money, but I think it’s a good thing to help the less fortunate who are far away and speak a different language.