This is likely insignificant, yet gives some hope. Japan may yet refrain from becoming a pawn, as it would surely be obliterated in a conflict with China. Unfortunately, this is probably but a squabble over blame for imperial incompetence.
Cup half full: either Japan is incompetent or ths US was and is trying to pin the blame on Japan, which will push them away. It could also be a pretext to warn Japan it can be dropped military in an attempt to draw them in, a sort of threat or loyalty test. Either way, imperial disunity favors multipolarity and AES.
Well, Japan has a history of recognizing it is small, limited in resources, and must adopt systems that work instead of going it alone. It's possible that, having done this a couple times already, they are now very aware of what works and what doesn't and are biding their time before the inevitable fall of the West makes it safer for them to "pivot to Asia".