Evidence of the retreat of good people faced with aggressive people. We need institutions that recognize social norms as property and allow for their defense (with violence).
For example Pinker complacently observes that the Victorians were shocked and horrified by a crime wave, but neglects to observe that this crime wave consisted of one mugging in London every few months – which crime wave never went away, but instead people got used to it, and then it got vastly worse, and people got used to it again, and then it got vastly worse still, and people attempted to abandon much of their cities to savages, and then the crime wave followed them, and there is now no safe area in London. The idea of the inner city as some kind of jungle is new, starting in the late nineteen forties, early fifties. Early in the twentieth century, the idea that the affluent and respectable might have to abandon vast expanses of wealth and property, of huge, beautiful and high status buildings where once the wealthy and fashionable lived, to the vandalism and depravity of savages would have been as unimaginable as wolves and bears prowling the streets of London to devour passers by.