Desperate times call for desperate measures.
FDR was honestly quite an effective president during WW2. However, many of his population dispersal programs, such as the ones for the Japanese, were under much criticism.
FDR wanted all Japanese civilians out of America in short since they could not be trusted as Japan was an enemy to the state. Dispersing the Japanese populations within America, in contrast, would tip the presidential elections at the time to FDR. These events followed Pearl Harbor. This is indirectly a violation of democracy, but happens all the time today: gerrymandering.
FDR tried everything he could to limit the rule of the axis powers in the Pacific and Europe. Some of these policies seem harmful, but war calls for desperate measures against the enemy to the state in order to protect the American people.
At least FDR wasn't the president to drop the bomb on Hiroshima...
His programs during the Great Depression seemed too much like Socialism.
The very wealthiest Americans during the Great Depression were insulated from its effects--it's hard to "buy low and sell high" if the stock market doesn't take a dip now and then--but the people who were affected, whose unemployment wasn't ending, whose savings were wiped out and whose homes and farms were being foreclosed on, required unprecedented government assistance.
The wealthy, then as now, tend to see poverty as the result of weak character, and their own wealth as the result of their own personal qualities. They saw the National Recovery Act and related programs as rewarding laziness, at the (wealthy) taxpayer's expense. They also felt personally inconvenienced by his "bank holidays," which limited their access to their own wealth. And since Roosevelt was from the same class as them, they saw him as a class traitor.
America had a long tradition of staying out of Europe's wars, and making an exception for the last two years of World War One put America deeply in debt. Conservatives opposed any effort to "needlessly" drag us into another foreign war.