Everypony is doing their part to fight the forces of Sombra and the Crystal Empire. On the front lines, Soarin sees the horrors of fighting an endless army of mind-controlled soldiers firsthoof. It's enough to make anypony lose hope.
It's why he looks forward to the shipments from home so much. And more importantly, the pony bringing those shipments. Sometimes, all you need is one reminder that there's something to fight for.