You could say other people's problems are their own. You could say America does more harm than good, or that we back the wrong horse or have no standards or don

You could say other people's problems are their own. You could say America does more harm than good, or that we back the wrong horse or have no standards or don't uphold public good. All those are points you could make. But, you asked what they'd die to protect if we fought ISIL. This is not an absurd question. In the case of ISIL, soldiers would die to protect the innocent civilians of Iraq and Syria, who are basically good people, and protecting everyone in the world from a group that uses videos of brutal execution-style murders as viral marketing from getting access to weapons of mass destruction, which are definitely not far away (Syria has had chemical weapons facilities captured before). That's not a bad thing to risk your life over. Stopping the Nazis 77 years ago was also a pretty defensible thing to do, not sure why you're using that as one of your examples wars that make "no sense whatsoever".