It's reasonable to expect all people to refrain from credibly threatening the lives of others.
Sorry, but it really is unreasonable to expect ALL people from credibly threatening the lives of others. After all, these are people we are talking about. Maybe you don't have a lot of experience with people, but some are really messed up. Since we are talking about credible threats, it's reasonable for us to kill anyone who makes these credible threats.
As a disclaimer I'll point out that the above threat is not credible.
Plastic came out of the earth. The earth probably sees plastic as just another one of its children. Could be the only reason the earth allowed us to be spawned from it in the first place. It wanted plastic for itself. Didn’t know how to make it. Needed us. Could be the answer to our age-old egocentric philosophical question, “Why are we here?”
~George Carlin
"Been through Hell? Whaddya bring back for me?" -- A. Brilliant