I really don't know where you're pulling that from. Jim Crow America wasn't a good time for black people. Women got lobotomy after showing the first signs of depression. Gay people were demonized at every occasion.
A return to this awful social hierarchy is MAGA and the right's ultimate goal, no matter how unrealistic. They're dismantling the Civil Rights act piece by piece, just last week they've been able to gerrymander the black vote away thanks to SCOTUS.
Like it or not, every social progress in this country has come from the left.