The actual answer is: They feared it would lead to United States involvement in World War II. I just took the test and got it right. 2/4/2019
Instead of staying completely out of the rising fears of war in Europe, President Roosevelt seems to advocate one side over another. Therefore, many Congressmen feared the speech would lead to United States involvement in World War II. Whether or not the speech accomplished that, the U.S. would eventually be greatly involved in the war.
And I did USAtestprep :)