Not denying people are unprincipled - but the wider set of trolley-style problems don’t really have a clear solution lack of self-interest would solve. If pushing one bystander onto the track to save five people is clearly, consistently right, why not take one random healthy hospital visitor and disassemble him or her for multiple life-saving organs?
Getting some kind of universal ethical system with clear, consistent answers to all question is really hard. And that’s not even getting into interpersonal differences in core values…
