Why didn't democracy address concerns of fascism and communism during the Great Depression?

Because Americans were much more concerned about matters at home than about foreign entanglements. It took a lot of effort to get Americans interested in joining WW2.

Here are some historical essays that might interest you. The one dated Nov. 15 is about the depression. www.shtfplan.com/category/howard-katz
More by the same author: www.gold-eagle.com/authors/howard-s-katz