He saved the world from the excesses of the Tyrant Trump.
Things to consider:
1) When dealing with a megalomaniacal tempertantrum-throwing game show host with access to the nuclear arsenal of the United States, you have to say, "look, I need to use my position to maybe push back and say, no, Trump, you can't fire nukes because you're mad you lost the election."
2) Given #1, you would also consider speaking to another world superpower and saying, "hey, look. Our leader is a tempertantrum-throwing fool, and just so you know, it won't be like this when Biden comes in. So just bear with us, please." You know, like adults do -- they talk things out.
3) The world has been saved by Milley, as he literally averted nuclear fucking war.
4) Anyone criticizing Milley for this should be ashamed of themselves.