At an emotional funeral service for a New York City imam and his assistant who were gunned down on a Queens street, one friend of the victims took the microphone and demanded that the city install security cameras outside mosques citywide to help protect Muslims from harassment or violence. “Each street corner should have security cameras around our places of worship,” said Anwar Hussein Khan, a teacher. But in the days following that impassioned plea, the city’s Muslim community has since backed away from that request. Muslim activists and civil liberties groups here have spent years opposing police surveillance of...