But what if they are wrong. The other countries aren't really doing anything on Taiwan except Lithuania which China dealt with.
It seems Japan didn't expect China to react this much which is why they need to double down to not lose face.
As for Japan re-arming, unless you swallowed the Kool aid about Japan learning it's lessons, it was always gonna happen in the future. Maybe you can delay it but one day you will need to be prepared for it.
They’re only wrong if China takes decisive, significant action. Otherwise, it’s a gamble that pays off, renews japans value in the eyes of America, and firms up domestic political standing. Any possible economic backlash they’ll just play victim and galvanize the japanese public.