Japanese leftists have accomplished the impossible - they are even more myopic than U.S. leftists. What possible difference would this have made if the Japanese government and the U.S. government sat on it for a month? This doesn't "put the brakes" on anything, it kicks the normalization talks into the ashcan of irrelevancy. They're in desperate denial, as the hopeful reference to "just didn't deny it" indicates.
Well, they needn't feel alone. All over the world leftists just got the props kicked out from under then with this one. The world isn't actually one whit more dangerous now than it was before the announcement, it's just that some folks just got their blinders torn off their heads.