Perhaps, but it was not really possible for the US to do so. A much better question is why Britain and France didn't move more aggressively against Hitler in the 1930s. Much has been written on that subject, and I don't have much to contribute beyond regurgitating what I've read. I would just caution you to avoid blaming the Allies for the crimes of their enemies.
Many American's felt that way. The desire for isolation aside, in several speeches Lindburgh indicated his belief that America hadn't the capacity to defeat the Reich. A two front war wasn't contemplated. Needless to say the 1940s proved him wrong.
Am not blaming the Allies for the murderous sins of the enemies.
But where there is not active resistance to evil or even not enough resistance, then evil will prevail until it is destroyed.
The PERCEPTION was that America would not actively aid England or France nor the invaded and raped countries in Asia and the South Pacific.
If not for Pearl Harbor, the perception would have been substantiated much longer - maybe to the point where the Axis powers could not have been stopped.
As it was, they got damn close to that point. More than almost all persons realize.
The Allies' victory in WWII was by no means assured; and the true cost remains really beyond conception.
Yes. "Shame on us for not being able to stop the murderer for killing." It's a common ailment in the modern era.