I get that this is hyperbole, but it's really, really dangerous. A good number of people care very much. Whether there are enough people in the right places for the U.S. to get involved is an open question. But it doesn't actually take that many people to commit a country to war. Thinking that the other side is definitely bluffing and there's no chance at all they'll do anything is how disastrous Great Power wars that no one really wanted happen.