Context does matter. Sen. Joe Manchin (D-W.V.) says the president should use the words, but Manchin himself isn't generalizing; he's speaking of acts of ISIS and some who evoke the extremist group, not the whole of the Muslim community.
Regardless of whether Islamic doctrine calls for violence, there are those within the community who strongly believe Islam is inherently a peaceful belief system. It'll be a fruitless endeavor to school people on their own beliefs, and in attempting to do so will undoubtedly ensure nothing useful is achieved in the campaign to end violence.
