Most people admire FDR who dealt with WWII while having disabilities. I admire him for certain things while disagreeing with him on domestic programs. Yes - it is possible to admire someone for certain things and hating them for others. That is the case with Newt Gingrich as well.
That's not what he said though. He said he was the greatest president of the 20th century.
FDR is the reason we continue to suffer from ever growing gov't. Others before him can be blamed for laying the ground work, but the country got behind FDR and we were forever changed. FDR was a domestic albatross.