The Oscar-winning actor-director loves talking about his Massachusetts background. But while taping a 2014 episode of “ Finding Your Roots ,” the popular PBS series about genealogy, Affleck learned something about his family’s history he wasn’t so eager to share — he is a descendant of a slaveholder. In a transcript of the segment , Affleck said, “It gives me kind of a sagging feeling to see, uh, a biological relationship to that. But, you know, there it is, part of our history.” With each story about another Republican governor’s or legislator’s efforts to erase Black history from their state’s...