Shock, horror, grief: that’s the gamut of emotions most New Yorkers felt when they heard how Ismaaiyl Brinsley, a troubled, itinerant 28-year-old most recently from Georgia, had come to our city to fire four bullets into the police car occupied by officers Wenjian Liu and Rafael Ramos in Bed-Stuy, Brooklyn, killing both on December 20. And that’s what most leaders expressed as well, including Mayor Bill de Blasio, who conveyed his condolences to the bereaved families and called the murders an “attack on all of us.” Gwen Carr, who lost her son Eric Garner after a New York City policeman put him in a chokehold last July, said, “We are going in peace, and anyone who’s standing with us, we want you to not use Eric Garner’s name for violence,…