I thought people knew that airlines handle packages poorly. That’s why you don’t check-in valuables. Always carry it on, or at least check in with something that won’t break. Like a hardshell case for a guitar. I doubt he put it in a hardshell case.
What did this person think was going to happen? It’s like putting a laptop in a nylon bag, checking it into cargo, and expecting it to be handled with extreme care. Who do you blame: workers on a deadline or the dumbass who cannot pack his crap?
Screw him. You don’t put care in your own stuff, you deserve to have it broken.