Socialist Security going bankrupt is one reason to dis him.
The financial collapse of 2008 is another.
Until Obama, FDR was the only president to cause a depression inside a depression.
He stole the citizen's gold.
He raped the Constitution.
He betrayed Western interests at Yalta.
And sooooo much more that I'm not going to bother to list it.
Only Wilson keeps FDR from being the worst president ever, though some put Buchanan before him with some justification.