With an appropriations measure for containing guidelines for the Centers for Disease Control and Prevention set to hit the House floor next month, Speaker John A. Boehner reaffirmed Thursday that the agency should not study guns as a health issue, repeating a familiar line that “guns don’t kill people, people do.” “The CDC is there to look at diseases that need to be dealt with to protect the public health,” Boehner said. “I’m sorry, but a gun is not a disease.”