North Carolina rapper J. Cole visited Ferguson, Missouri, to demand justice for Michael Brown and protested in New York for Eric Garner, but none of that political fire burns on his third album “2014 Forest Hills Drive.” The rapper speaks some incisive truths about class, race and relationships, but those insights are too often undercut by crass humor. The production falls short, too, with dull beats to match his languid flow. It’s time for the Cole who marches in the streets to start showing up on record.