As much as Trump and Hegseth would like it to be called the Department of War, it still takes an act of Congress to change the name of the Department of Defense. No reason to call it by anything else until that happens.
Departament of defense sounds like a newspeak for a country that was not in any danger of being invaded for a century or more and all the wars abroad it participated in, it entered pretty much by choice. Department of war is way more accurate.
This is such a foot stomping childish thing to get caught up on. It does not at all matter what a dept is called. Try to get over the extremely superficial.