I'm not talking about boycotts in general, like say the Montgomery Bus Boycott, because we know those can work. I'm talking about "Company that sells product made me mad" boycotts.
Whether it's past ones like the infamous Call of Duty: Modern Warfare 2/Left 4 Dead 2 boycotts, or more recently like the brewing chud Pride Month boycotts (And if we're being brutally honest here on the flipside: The all-but-in-name boycott of that Harry Potter game a month or 2 ago), all of them seem to universally fail spectacularly and not impede their targets in any way.
The 1937 invasion of China wasn't caused by a boycott, it was caused by the Kwantung Army acting on its own without orders from Tokyo.
I'm obviously talking about things like the boycotts organized after the May Fourth Movement, Jinan Incident, and so on. I mean, duh.
I don't know much about it but I would be surprised if the tensions between the two nations didn't influence the Kwantung army's decision to act. It wasn't just a random event like a lighting strike