"In the age of Idle No More and Black Lives Matter, grievance is the glue that keeps groups such as these together."
Strange (not-strange) Yakabuski would pick those examples, considering so many people on the right are claiming Donald Drumpf's victory in the US was all about the anger and grievances of the white middle american. In the days of "mainstream media" and "smug liberal elites", it's grievances that keep not just left wing movements but entire right wing political parties together. 
Of course, the grievances of the protest groups are both real and historical, whereas the grievances of middle class white America are mostly illusory and based on the false notion that anyone else's equality reduces their privilege. 
But I suppose for some writers any time is a good time to smear the motivations and members of leftie groups, no matter how well the glove fits the other hand.