Possibly meant in the sense of Blue Tribe / Red Tribe from here: https://slatestarcodex.com/2014/09/30/i-can-tolerate-anything-except-the-outgroup/ https://slat

Possibly meant in the sense of Blue Tribe / Red Tribe from here: https://slatestarcodex.com/2014/09/30/i-can-tolerate-anything-except-the-outgroup/ https://slatestarcodex.com/2014/09/30/i-can-tolerate-anythin... But maybe it's just more generally red as euphemism for conservative (b/c of how political maps are coloured in the US).