Seriously, you pose an excellent question.
My Dad was the one that started my interest in this subject, Hopkins, back when I was a kid in the late 50s, before he died. He had spent some time in Russia during the war, convoy duties, and hated the Commies based on the treatment of the Russian people by their masters, his personal observation.
I was ten or twelve years old and the subject of Harry Hopkins came up and my father said he was a Commie spy, I was too young to question the reasoning behind the observation but it hung in my mind. My father believed that Roosevelt was the first dictator of the USA, he was in his twenties during the depression and had strong political views.
Currie and Hopkins were close advisors to FDR , in the White House, and he didn't meet a commie he didn't like, like his wife, for a short while any way. If you look at some of the positions that he took as Governor of NY, Power Athority and others, he was bent to the left. Commie, I don't know. My Grandfather thought that every Rat from Bryant on down was a commie in one form or another, but he was rather extream.