Plus the American involvement wasn't out of humanitarian reasons either. They only joined the war after getting attacked by Japan themselves. Which, which since I support retaliatory action if another party has already initiated war, would mean the US followed my stance on war in that regard.
Yes, war causes suffering. It can also prevent suffering. This would only be contradictory if I were for some reason arguing that all war is good, which I most certainly am not.
I would argue that the US did join the war partly out of humanitarian reasons, since the war was precipitated by economic sanctions that were enacted due to Japan's actions in China. But ultimately my argument has nothing to do with their reasons.
Because you are using the sorrow of war to justify the means of war. It's a cyclic argument with each new participant upping the stakes; each time bringing about more suffering.
In the case of the America vs Japan conflict during WW2, America's "humanitarianism" lead to two nuclear bomb being dropped causing around two hundred thousands casualties - many of who suffered long deaths from radiation exposure. Yes it shortened the war, but at what cost? We'll never know which hypothetical scenario would have saved the most lives but it's fair to say that America's involvement did contribute to large scale suffering too.
After Pearl Harbor everything fell into place. Germany and Japan could be tackled not from a diplomatic perspective, or via proxies, but directly.
