"1933 under FDR"?
I'm going to be blunt here: That's a complete load of horseshit.
First and foremost, FDR was sympathetic to Adolf Hitler (hence the U.S not entering World War II until we had literally no other choice after Pearl Harbor) and being the main outside supplier of weapons to Germany - yeah, FDR would have only sold weapons to the Axis powers had he been given his way. They were both left wing Democratic Socialists who incited radical changes in the government by feeding off of past "failures" of former establishments and giving out false promises of returning to better times in exchange for getting rid of the people and policies they pinned the blame on. (much like modern cancel culture, but I digress).
Secondly, Literally the only thing that FDR did that effected the "party shift" (which again, literally everyone else hiding behind it but you claims happened in the mid 50's to mid 60's, nearly twenty years *after* you are claiming it happened. If anything, claiming the "party shift" happened in the 30's only hurts your argument even more because it only increases the amount of racist shit Democrats have done after it. What's next, saying the "party shift happened before the civil war"?) was the policies he enacted to end the great depression, which - on paper - doesn't sound like a bad thing inadvertently set the U.S on a pathway of entitled people demanding government handouts, national debt, lowering the over all standard of living for everyone, not just blacks.
Third of all; FDR , despite being praised by Democrats as one of the best presidents ever, was a corrupt, and vile man who is only admired because he gave out a bunch of free crap. Here are a list of a few of the horrible things he's done:
1.) Literally Rounding Up 120,000 Japanese Americans, and put them in Concentration Camps. (This goes hand in hand with him being sympathetic to Adolf Hitler)
2.) He was Pen Pals With Mussolini, the fascist Dictator of Italy in league with Adolf Hitler during World War II. Even going as far as to say "I am keeping in fairly close touch with that admirable Italian gentleman,’ And the feeling was mutual, because Mussolini went on to say the following in reference to FDR “Reminiscent of Fascism is the principle that the state no longer leaves the economy to its own devices.… Without question, the mood accompanying this sea change resembles that of Fascism.”