I prefer rules-based utilitarianism, which is the idea that we should create a system of rules that achieves the most good when followed. If we created a system whereby we rounded up healthy people and forcibly harvested their organs "for the greater good", well, society would collapse as everyone flees to the woods to preserve their own life and organs. No farmers, no scientists, no doctors, no infrastructure maintenance, just global famine. And that would be a far worse net outcome than the current system that lets some people die prematurely due to lack of available organs.