Not enough coffee. Read what I said again: "Many people did not know...because the media supported him".
I was surprised by how long I myself did not know.
And now they think polio may have been a misdiagnosis, not that it would have helped him much at the time.
Not enough for sure. You don't know because you did not live in the time. Polio was so common then people understood it's effects so it would be like if he were blind commending that the president is still blind. I believe that FDR's crippled (the normal word then) state was known to the average man. Just there are some who are oblivious to almost anything.
Anyone and everyone at the time looking at this Yalta photo would have understood what the crossed legs meant. It is not subtle.
In any case was your point that the press can help underplay something fairly obvious? Yes and that is no revelation to anyone.
Regarding your other mention of Michelle Obama.. labeling her transsexual or gender was a slow news day at Breitbart or Infowars. Just made up and plainly so. Conspiracy brain gibberish leads to flat-Eartherism and Scientology.