This tradition goes back further than Roosevelt. In addition to being a notorious bigot and racist, Woodrow Wilson was open about the idea that the Constitution was outmoded and needed replacing so that a technocratic government could take its place.
You also have Roosevelt's first appointment to SCOTUS, a literal hood-wearing klansman and true-blue progressive. Broadly the progressive movement was also home to a high level of racism; more of the paternalistic variety than the hateful, but still led to e.g. forced sterilizations. Progressives today have abandoned that, but there was no such radical realignment for them.
