Second Amendment supporters might sound like an unlikely ally for Hunter Biden as the president’s son appeals his gun conviction. But that’s the advice of CNN political commentator and former Republican presidential campaign staffer Shermichael Singleton, who shared an emotional anecdote Thursday about learning as a youth the value the Second Amendment holds for Black men in the South. “I remember my grandfather telling us how, in his day, a firearm was the only way a Black man could protect himself and his family against racists who wanted to teach Blacks a lesson,” Singleton wrote. “He would…