Apparently they got coerced by the current US admin. The department of war in particular, who want to use their products for military applications. Not much room for "safety" there. Then again, the entire US is currently speedrunning an evil build.
Department of Defense is the official name, and they did have a choice: they could have stopped working with the military. But they chose money and evil.
Not sure what you mean by "official." They call themselves that way:
https://www.war.gov/
It doesn't matter that there exists another name on some paper, when all official, ceremonial and public communications use this name. The old name is about as worthless as the constitution or the senate at this point. The executive branch has successfully taken over the country.
