They do in fact manufacture them.
Both Osama bin Laden and the new ISIS leader were both trained by the US State Department.
They weren’t the only ones. State/CIA has poured billions into Syrian jihadis in recent years, at least in part due to Saudi patronage of one Hillary Rodham Clinton.
I don’t buy into that blame the US nonsense. We didn’t manufacture terrorists. They exist regardless of what we do. They hate the west and have been around since Mohammed.