Colin Kaepernick and San Francisco 49ers safety Eric Reid kneeled during the national anthem Thursday night, continuing the quarterback’s preseason protest of American racial injustice and minority oppression.Kaepernick and Reid dropped to one knee while a naval officer sang “The Star-Spangled Banner” and dozens of military members unfurled an oversized flag at the Chargers’ Qualcomm Stadium. Kaepernick received scattered boos when he dropped to a knee, but the protest was otherwise unremarked by the San Diego crowd. The 49ers’ visit coincided with the annual Salute to the Military preseason game for the Chargers, who have strong fan support in their...