FDR was a bit of a racist which get glossed over, in his world if you were not WASP, you were not anything of importance apparently. But it would have been interesting if John Nance Gardner had been president. But arguably FDR did reasonably well as a wartime president, but I argue he was too eager to get us into a European dust up.
In contrary to that, I think he was too eager to get involved with trying to save China from Japan. But what it really was in trying to save CKS's China from Japan and its Reorganized China government with Wang Jingwei on top. The US started sending lines of credit to the Nationalists Chinese in December 1938, the first one being 25 million USD, which apparently was enough to keep CKS from losing control of the nationalists Chinese. 20 million line of credit in March 1940. Then 100 million in November 1940. http://www.nids.mod....f/201303/09.pdf
There could be an argument making a case for geopolitical and security interest position for the US to have steadily become more and more vested in the survival of the nationalist Chinese for the purpose of balancing Japan and preventing a larger Japan sphere of influence over mainland China. But arguments that urge the backing of the nationalist Chinese on the basis of justice is naive because how can one claim that CKS (or the SU for that matter) be more respectful towards human rights than Japan or the Collaborative regime under Wang? Even if Japan was not the ideal role model, I'm not convinced the other players in the region were any better. In the end, our timeline resulted in the other party winning, Mao. My very unpopular view. Why go into it, only because I'm not sure if your post is implying a view saying "that path towards war vs Japan was good and path towards war vs Germany was bad".
But Nazi Germany had to be taken out. It was unfortunate that Japan drew closer to Germany in the process. I would like to think that had the other major powers been less critical of Japan taking Manchuria, than maybe CKS and other nationalistic sentiments would have been avoided in starting trouble with the Japanese in places like at the Marco Polo bridge. But that's how history played out and Imperial Japan was not pretty anyway. Life goes on. But a view about today's security relation between the US and other European countries which might be increasingly against such defense relations really should have no bearing on changing the established view that eliminating that regime was a good thing.
I cannot disagree with this.