There is a strange disconnect amongst progressives that suggests evolution is somehow predictable, automatic, assured, impossible to reverse, temporarily or permanently. Darwinism do seem to confirm that physically such a premise is correct, but matters of conscience, opinion, belief are for more transitory and prone to sudden and extreme resets, against the tides of time, sensibility, and progress.
Such recessions can be diagnosed as symptoms of fear, concern for loss of power, influence, control. They particularly relate to matters of developing sensibility, when the new generations are inclined to lead the past by weight of numbers, or intellectual clarity, dragging their predecessors shadowy viewpoint into the glaring brilliance a better and more enlightened present.
Such anomalous setbacks will in good measure be addressed, corrected, for progress is a river that untimely flows but in one direction, overcoming obstacles, dams, natural or constructed from gathered detritus. Truth is remarkably resilient and lumined.