That term has been defined as law for decades in some states. It's not a new phenomenon
I was on an attempted murder jury and that was one of the three charges...(I was an alternate, so sat out the deliberations - they found him not guilty of that).
It's kind of an "add-on" piling on thing by the DA. It applies if you address your target before you pull the trigger - such as "I'm going to kill you"; hence you've made a threat.