knuckle-dragging

From the habit of some primates of walking with the forelimbs dragging along the ground.

knuckle-dragging (not comparable)

1. (derogatory) Holding beliefs or having attitudes that are primitive or uncivilised.
   • 2018 June 15, Hanif Kureishi, “Diversity in publishing is under attack. I hear the sound of knuckles dragging”, in The Guardian‎:

     The furore over Penguin's wise and brave decision to “reflect the diversity of British society” in its publishing and hiring output seems to have awoken the usual knuckle-dragging, semi-blind suspects with their endlessly repeated terrors and fears.