A San Jose police officer involved in a controversial shooting last year resigned after investigators discovered a trove of racist text messages on his phone, including some that made light of the shooting and referred to the victim by a racial epithet, as well as one that said “I hate Black people.” Last March, the officer — Mark McNamara, who is white — shot a Black man who helped disarm an instigator in a bar fight as he backed out of the door with the confiscated gun in his hand. The department’s chief called the texts “disgusting and horrible.”