I'm talking about the ~6 million estimated violent crimes that occur each year. Many, many of those are deadly threats. Any that involve a weapon are automatically deadly threats. Any involving multiple attackers are deadly threats. Any that involve a significant advantage in physical force of the attacker over the target are deadly threats. In general, any that involve the attacker being in a position to cause death or grave bodily harm are considered deadly threats, and can be legally met with lethal force if that is necessary to stop the threat.

I'm not sure what world you are living in. There are millions of people who are victims of violent crime each year in the US. It happens. A lot.