> but i wouldn't consider a leader who operated concentration camps to be leftist by any stretch.

I consider myself a leftist, but it's a bit naive to think that "this bad, horrible thing" must be associated only with right-leaning ideology. Leftists can do bad, horrible things just as much as right-wing folks can. "Putting people in concentration camps" isn't a right-wing or left-wing thing, it's a totalitarian/anti-human-rights thing. We can argue that, as of late, right-wing people seem to have more of an appetite for that sort of thing, and I'd probably agree, but that doesn't make concentration camps a "right-wing thing".

I would absolutely consider FDR to be one of the most (if not the most) leftist presidents the US has had. His putting people in concentration camps doesn't change that; it just makes him a racist piece of shit, like so many others of his time (not that the time period excuses it).