No, it is not, because bank robbery is against the law. As long as abortion is not against the law, threats are a crime.
This is a nation of laws, not necessarily morality.
So9
If, as a Yankee fan (in baseball and not the War of Yankee Aggression), I shout at Red Sox fans: You will never win a World Series in your lifetime or God's lifetime, it is of course not a threat because: 1) it is a reality as an immutable result of the curse of the Bambino; and 2) I am not personally capable of making them lose since I am neither the Bambino nor am I god nor am I even Alfonso Soriano.
As witness the persecution of a woman for having the effrontery to read the actual Bible in the Godless presence of a heathen child-killer, in light of Roe vs. Wade and its, ummm, progeny, and the life work of SCOTUS since 1936, and the remarkable usurpation that occurred in Marbury vs. Madison and several historical controversies near and dear to your heart and mine, we are most certainly NOT a nation of laws.
So, by that logic, "If you keep smoking, it's going to kill you" is a "threat," right? Of course it is.
A threat is when I tell you I am (or someone who answers to me is) going to do something bad to you. Merely telling you something bad is going to happen to you, without indicating that I myself am the agent, is not a threat, it's a warning.