Threatening to kill people, even in a subtle manner is wrong. Sending people in the area to follow-up on something that was paid for and not delivered, is totally within his rights. You just assume they would do bad things because you THINK that way... He posted your email about how you have plenty of ammo and just sighted your rifles in...
So you'd kill someone over a few dollars, really nice. And you'll probably claim you're doing what's within your rights...
"I have a gun, and I'll use it to impose my will and demonstrate how I am able to make whatever I want right, by any means." A cowards creed. People who think like that suck... A mature gun owner would never refer to the use of deadly force as a first response...
SAD.