The problem is that FDR could not keep us out of the war and he knew it. But others were promising the same and they were completely clueless, there was no way for anyone to keep us out of that war. So which was better, FDR who knew we were going to war or the complete fuck ups who promised to keep us out of a war they couldn't at all?
To me the completely clueless were not capable of guiding us through a war. Anyone who was sensible at that time knew that escaping war wasn't going to happen. Esp with the Japanese who were claiming the same territory as the US was and building up their military. The Japanese made it clear that unless the US backed down in the pacific, they were taking what they wanted, which included the philippines and many islands the US controlled.
Now maybe the US public should have stated that we would be willing to relinquish the territory and just give the pacific to the Japanese if they didn't want a war. It wouldn't have solved Europe and england, but the Japanese wouldn't have felt they needed to attack us. Then we could have stayed out of europe and let england fall. And at some point in time Hitler would have attacked the US. Because that would have happened. And with a strong-pro hitler support in the US, we would have folded quickly with an anti-war person in charge.
Anyone who thinks we could have avoided WWII would either have surrendered to Japan or Germany or doesn't understand the history that led to the war.